Growatt inverter error and warning codes explained
Growatt inverters show codes as "Error" or "Warning" followed by a number, or as a short message such as AC V Outrange. The same number can mean different things as an Error and as a Warning (for example Error 203 and Warning 203), so check both the word and the number. Codes are grouped by model family below.
Safety first, please read
- Solar panels and batteries produce dangerous DC voltage whenever there is daylight or charge in the battery, even with the mains switched off. Electrical work on these systems must only be done by a licensed electrician.
- Never open the inverter or battery, and don't unplug, touch or adjust DC cables, connectors or isolators except for the owner shutdown steps in your manufacturer's manual.
- For an isolation/insulation fault, earth fault, arc fault, residual-current fault or battery over-temperature alarm, or any smoke, burning smell, hissing, swelling, leaking or water damage: only switch off if the manufacturer's procedure lets you do it safely, keep everyone clear, and call a licensed electrician or Total Solar.
- If there is fire or smoke, get everyone out and call 000. Tell the fire service there is a solar and battery system on site.
- Don't climb on the roof to check or clean panels. Do checks from the ground only.
Owner shutdown and restart (Growatt)
Growatt's MIN TL-X manual gives this turn-off order: switch off the inverter's AC circuit breaker, then turn the inverter's DC switch off, then wait until the screen and LEDs go out. Start-up is the reverse: AC breaker on, then DC switch on. Hybrid (SPH/SPM) systems with batteries have extra steps, so follow your model's manual and only do this if your installer has shown you how.
- SPH 3000-6000TL BL-UP hybrid
- MIN TL-X / MIN TL-XH / MIC TL-X (single-phase)
- MOD TL3-X (three-phase)
- Growatt Australia Helpdesk articles (MIC/MIN/MOD/SPH with smart meter)
- SPM 8000-10000TL-HU hybrid (Helpdesk troubleshooting guide)
SPH 3000-6000TL BL-UP hybrid (32 codes)
Warning 401SP-CT/Meter Communication faultWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 203PV1 or PV2 Circuit shortFault
What it means: The inverter suspects a short circuit or reversed polarity on solar input PV1 or PV2.
Likely causes:
- Polarity error during installation or maintenance
What you can safely do:
- Do not touch any DC wiring
- Call us or a licensed electrician
Warning 506Battery temperature out of specified range for charge or dischargeWarning
What it means: The battery temperature is outside the range allowed for charging or discharging, so battery use is paused.
Likely causes:
- Battery too hot or too cold for its location
What you can safely do:
- Check the battery area isn't in direct sun or freezing conditions and the vents are clear
- Wait for the temperature to return to normal
- If the battery is hot to the touch, smells or is swelling, keep clear and call us (000 if there is smoke or fire)
AC V OutrangeGrid voltage faultWarning
What it means: The mains voltage the inverter measured was outside the limits allowed for your network, so it disconnected or reduced output to protect the grid. This is usually a grid condition, not a faulty inverter.
Likely causes:
- High street voltage, common on sunny afternoons when many homes export solar
- Grid disturbances or voltage dips
- Long or undersized AC cabling between the inverter and the switchboard (installation issue)
- Grid protection settings that don't match your network's requirements
What you can safely do:
- Wait. The inverter reconnects by itself once voltage is back within limits
- Note the time of day it happens. If it happens most sunny days, tell us, because it may need a voltage check or a report to your network operator
- Don't try to change grid protection settings yourself. In Australia they are set to AS/NZS 4777.2 and your network operator's requirements
AC F OutrangeGrid frequency faultWarning
What it means: Grid frequency moved outside the allowed range, so the inverter disconnected or reduced output as the standards require.
Likely causes:
- Short grid disturbance
- Running on a generator or a weak supply
- Grid settings that don't match the local network
What you can safely do:
- Wait for automatic reconnection
- If it happens often, record the times and contact us
PairingTimeOutSP-CT communication fault (pairing timeout)Warning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
CT LN ReversedSP-CT L and N reversedWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
BMS COM FaultBattery (BMS) communication faultFault
What it means: The inverter and battery (or parts inside the battery) have stopped talking to each other, so the battery may stop charging or discharging.
Likely causes:
- Battery switched off or in a protection state
- Loose or damaged communication cable
- Firmware or settings mismatch
What you can safely do:
- Check the battery's indicator lights and your monitoring app for other alarms
- Don't unplug or re-plug cables yourself
- Call us if it does not clear within a few hours
Battery reversedBattery terminals reversedFault
What it means: A solar string or the battery appears to be connected with positive and negative swapped.
Likely causes:
- Polarity error during installation or maintenance
What you can safely do:
- Do not touch any DC wiring
- Call us or a licensed electrician
BAT NTC OpenBattery temperature sensor open (lead-acid only)Fault
What it means: The battery management system has reported a problem with battery voltage, current, cells or internal hardware and has limited or stopped battery operation.
Likely causes:
- Cell voltage or capacity imbalance
- Over-charge or over-discharge conditions
- Internal battery hardware (relay, sensor, circuit board) fault
- Firmware or configuration mismatch between battery modules
What you can safely do:
- Do not open the battery or touch its terminals
- Note the exact alarm text and time from the app
- Call us. Battery faults should be handled by the installer or manufacturer
Battery OpenBattery terminal open (lithium)Fault
What it means: The inverter and battery (or parts inside the battery) have stopped talking to each other, so the battery may stop charging or discharging.
Likely causes:
- Battery switched off or in a protection state
- Loose or damaged communication cable
- Firmware or settings mismatch
What you can safely do:
- Check the battery's indicator lights and your monitoring app for other alarms
- Don't unplug or re-plug cables yourself
- Call us if it does not clear within a few hours
Over LoadEPS output overloadWarning
What it means: The EPS/backup output is overloaded. Growatt notes that after three overloads the off-grid function locks out for an hour before trying again.
Likely causes:
- Too much load on the EPS (backup) output
What you can safely do:
- Switch off large appliances on backup circuits
- Wait for the system to retry (some models lock out for a period after repeated overloads)
- If it trips with only small loads on, or you suspect a short circuit, call an electrician
No AC ConnectionNo utilityWarning
What it means: The inverter cannot see a normal mains supply, so it has stopped exporting to the grid (and a hybrid system may switch to backup).
Likely causes:
- Power outage in your street or area
- A tripped or switched-off solar/inverter circuit breaker in the switchboard
- Loose AC connection between the switchboard and the inverter
What you can safely do:
- Check whether the rest of the house (or your neighbours) has power, and check your network operator's outage map
- Check the switchboard for a tripped solar supply main switch or inverter breaker. Only reset it once. If it trips again, leave it off and call an electrician
- Wait. Once normal grid power is back, the inverter normally reconnects by itself after its safety checks (often a few minutes)
- If grid power is normal but the alarm stays, call us
Output High DCIOutput DC current too highFault
What it means: The inverter detected too much DC current in its AC output, which the grid standards don't allow, so it disconnected.
Likely causes:
- A one-off disturbance (if it is occasional)
- Internal measuring or power stage problem (if it repeats)
What you can safely do:
- If it happened once and the system recovered, keep an eye on it
- If it repeats, call us
Bat Voltage HighBattery voltage higher than 60VFault
What it means: The battery management system has reported a problem with battery voltage, current, cells or internal hardware and has limited or stopped battery operation.
Likely causes:
- Cell voltage or capacity imbalance
- Over-charge or over-discharge conditions
- Internal battery hardware (relay, sensor, circuit board) fault
- Firmware or configuration mismatch between battery modules
What you can safely do:
- Do not open the battery or touch its terminals
- Note the exact alarm text and time from the app
- Call us. Battery faults should be handled by the installer or manufacturer
Bat Voltage LowBattery voltage lower than 42VInfo
What it means: The battery's state of charge or voltage is low, so the system has stopped discharging it to protect the cells.
Likely causes:
- Battery has been used down to its reserve level
- Several cloudy days with little solar to recharge
- Charging is disabled by the settings or by another fault
What you can safely do:
- Allow it to recharge from solar (or the grid, if your settings allow)
- Check the app for other alarms that could be stopping charging
- If it stays low for days in good sun, call us. Batteries left flat for long periods can be damaged
BMS Warning:XXXBMS reports a warningFault
What it means: The battery management system has reported a problem with battery voltage, current, cells or internal hardware and has limited or stopped battery operation.
Likely causes:
- Cell voltage or capacity imbalance
- Over-charge or over-discharge conditions
- Internal battery hardware (relay, sensor, circuit board) fault
- Firmware or configuration mismatch between battery modules
What you can safely do:
- Do not open the battery or touch its terminals
- Note the exact alarm text and time from the app
- Call us. Battery faults should be handled by the installer or manufacturer
BMS error:XXXBMS reports an errorFault
What it means: The battery management system has reported a problem with battery voltage, current, cells or internal hardware and has limited or stopped battery operation.
Likely causes:
- Cell voltage or capacity imbalance
- Over-charge or over-discharge conditions
- Internal battery hardware (relay, sensor, circuit board) fault
- Firmware or configuration mismatch between battery modules
What you can safely do:
- Do not open the battery or touch its terminals
- Note the exact alarm text and time from the app
- Call us. Battery faults should be handled by the installer or manufacturer
EPS Volt LowEPS output voltage lowWarning
What it means: The backup/EPS (off-grid) output is overloaded or abnormal, so the system has limited or switched off backup power.
Likely causes:
- Too many or too large appliances on backup circuits during an outage (for example ovens, air conditioners, pumps)
- High start-up surge from motors or compressors
- A short circuit on a backup circuit
What you can safely do:
- Switch off large appliances on backup circuits
- Wait for the system to retry (some models lock out for a period after repeated overloads)
- If it trips with only small loads on, or you suspect a short circuit, call an electrician
Error 411Internal communication failedFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 417Sample faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 418DSP and COM firmware version unmatchFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Error 303Inverter L N reversed or ground failed (NE abnormal)Safety-critical
What it means: The inverter has found active and neutral reversed, or a missing or poor earth. Growatt's manual says this code is also how an earth fault alarm shows on this model.
Likely causes:
- Loose or missing earth connection on the inverter or array
- Neutral and earth problem in the AC wiring or switchboard
- Fault in the building's main earth
What you can safely do:
- Do not touch the inverter, frames or cabling
- Leave the system off if it has shut down. Call a licensed electrician or us to test the earthing
Error 405Relay faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 123Autotest failed (Italy only)Fault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
PV Isolation LowPV isolation too lowSafety-critical
What it means: The inverter measured low insulation resistance between the solar/battery DC circuits and earth. In Australia this is treated as an earth fault alarm, and the system must be checked by a licensed electrician.
Likely causes:
- Damaged DC cable insulation (for example from rodents, UV or a pinched cable)
- Water in a DC connector, isolator or junction box
- A damaged solar panel or backsheet
- Heavy dew or rain can trigger it temporarily on marginal systems
What you can safely do:
- Do not touch panels, DC cables, rooftop isolators or the inverter's DC connectors
- If it clears by itself after the weather dries out, still report it, because repeated alarms point to a developing fault
- Book an electrician or call us. An insulation test needs specialist equipment
- If you see smoke, burn marks or smell burning, keep clear and call 000
OP Short Fault!EPS output short faultWarning
What it means: The backup/EPS (off-grid) output is overloaded or abnormal, so the system has limited or switched off backup power.
Likely causes:
- Too many or too large appliances on backup circuits during an outage (for example ovens, air conditioners, pumps)
- High start-up surge from motors or compressors
- A short circuit on a backup circuit
What you can safely do:
- Switch off large appliances on backup circuits
- Wait for the system to retry (some models lock out for a period after repeated overloads)
- If it trips with only small loads on, or you suspect a short circuit, call an electrician
NTC OpenInternal temperature sensor failedFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 406Model set-up does not meet certificationFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Residual I HighLeakage current too highSafety-critical
What it means: The inverter measured leakage (residual) current flowing to earth above its safety limit and disconnected. This can indicate damaged insulation somewhere in the system.
Likely causes:
- Damaged DC or AC cable insulation
- Moisture in connectors or equipment
- A one-off disturbance (if it happens once and never again)
What you can safely do:
- Don't touch cabling or equipment
- If it happens repeatedly, or together with an insulation/isolation alarm, call an electrician or us promptly
Error 408Temperature over rangeWarning
What it means: The inverter is running too hot, so it has reduced output or paused to protect itself.
Likely causes:
- High ambient temperature or direct afternoon sun on the inverter
- Blocked air vents or heat sink (dust, cobwebs, stored items)
- A fan problem (on fan-cooled models)
What you can safely do:
- Make sure nothing is stacked against or in front of the inverter, and leave the manufacturer's clearances around it
- Gently clear dust or leaves from the outside of the vents, without opening the unit or spraying water
- Let it cool. It normally resumes by itself
- If it keeps happening on mild days, call us
PV Voltage HighPV voltage higher than datasheetFault
What it means: The DC voltage coming from the solar panels is higher than the inverter is rated for. Over-voltage can damage the inverter.
Likely causes:
- Too many panels wired in series in a string (system design/installation issue)
- Very cold, bright mornings raise panel voltage
- Incorrect panel or string configuration after a change to the system
What you can safely do:
- Do not touch the DC isolator or cables unless the manufacturer's owner shutdown tells you to
- Call us. The string design needs to be checked by a licensed installer
MIN TL-X / MIN TL-XH / MIC TL-X (single-phase) (27 codes)
Error 201Residual I High (leakage current too high)Safety-critical
What it means: The inverter measured leakage (residual) current flowing to earth above its safety limit and disconnected. This can indicate damaged insulation somewhere in the system.
Likely causes:
- Damaged DC or AC cable insulation
- Moisture in connectors or equipment
- A one-off disturbance (if it happens once and never again)
What you can safely do:
- Don't touch cabling or equipment
- If it happens repeatedly, or together with an insulation/isolation alarm, call an electrician or us promptly
Error 202PV Voltage HighFault
What it means: The DC voltage coming from the solar panels is higher than the inverter is rated for. Over-voltage can damage the inverter.
Likely causes:
- Too many panels wired in series in a string (system design/installation issue)
- Very cold, bright mornings raise panel voltage
- Incorrect panel or string configuration after a change to the system
What you can safely do:
- Do not touch the DC isolator or cables unless the manufacturer's owner shutdown tells you to
- Call us. The string design needs to be checked by a licensed installer
Error 203PV Isolation LowSafety-critical
What it means: The inverter measured low insulation resistance between the solar/battery DC circuits and earth. In Australia this is treated as an earth fault alarm, and the system must be checked by a licensed electrician.
Likely causes:
- Damaged DC cable insulation (for example from rodents, UV or a pinched cable)
- Water in a DC connector, isolator or junction box
- A damaged solar panel or backsheet
- Heavy dew or rain can trigger it temporarily on marginal systems
What you can safely do:
- Do not touch panels, DC cables, rooftop isolators or the inverter's DC connectors
- If it clears by itself after the weather dries out, still report it, because repeated alarms point to a developing fault
- Book an electrician or call us. An insulation test needs specialist equipment
- If you see smoke, burn marks or smell burning, keep clear and call 000
Error 300AC V OutrangeWarning
What it means: The mains voltage the inverter measured was outside the limits allowed for your network, so it disconnected or reduced output to protect the grid. This is usually a grid condition, not a faulty inverter.
Likely causes:
- High street voltage, common on sunny afternoons when many homes export solar
- Grid disturbances or voltage dips
- Long or undersized AC cabling between the inverter and the switchboard (installation issue)
- Grid protection settings that don't match your network's requirements
What you can safely do:
- Wait. The inverter reconnects by itself once voltage is back within limits
- Note the time of day it happens. If it happens most sunny days, tell us, because it may need a voltage check or a report to your network operator
- Don't try to change grid protection settings yourself. In Australia they are set to AS/NZS 4777.2 and your network operator's requirements
Error 302No AC connectionWarning
What it means: The inverter cannot see a normal mains supply, so it has stopped exporting to the grid (and a hybrid system may switch to backup).
Likely causes:
- Power outage in your street or area
- A tripped or switched-off solar/inverter circuit breaker in the switchboard
- Loose AC connection between the switchboard and the inverter
What you can safely do:
- Check whether the rest of the house (or your neighbours) has power, and check your network operator's outage map
- Check the switchboard for a tripped solar supply main switch or inverter breaker. Only reset it once. If it trips again, leave it off and call an electrician
- Wait. Once normal grid power is back, the inverter normally reconnects by itself after its safety checks (often a few minutes)
- If grid power is normal but the alarm stays, call us
Error 303PE abnormal (N-PE voltage above 30V)Safety-critical
What it means: The inverter detected a problem with the earth (protective earth/PE) or with the neutral-to-earth connection. A sound earth is essential for electrical safety.
Likely causes:
- Loose or missing earth connection on the inverter or array
- Neutral and earth problem in the AC wiring or switchboard
- Fault in the building's main earth
What you can safely do:
- Do not touch the inverter, frames or cabling
- Leave the system off if it has shut down. Call a licensed electrician or us to test the earthing
Error 304AC F OutrangeWarning
What it means: Grid frequency moved outside the allowed range, so the inverter disconnected or reduced output as the standards require.
Likely causes:
- Short grid disturbance
- Running on a generator or a weak supply
- Grid settings that don't match the local network
What you can safely do:
- Wait for automatic reconnection
- If it happens often, record the times and contact us
Error 407Auto Test FailedFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 202DC SPD function abnormalFault
What it means: A surge protection device (SPD) inside or connected to the inverter is reporting a fault, often after a lightning storm or grid surge.
Likely causes:
- SPD has done its job after a surge and now needs replacing
- SPD wiring fault
What you can safely do:
- Don't open the inverter
- Call us. SPDs must be replaced by a licensed electrician
Warning 203PV1 or PV2 Circuit shortFault
What it means: Growatt's manual describes this as a short circuit on solar input PV1 or PV2 and suggests checking panel polarity, which is a job for an electrician.
Likely causes:
- Polarity error during installation or maintenance
What you can safely do:
- Do not touch any DC wiring
- Call us or a licensed electrician
Warning 204Dry contact function abnormalInfo
What it means: The system has received a shutdown or control signal, or a protective input has been triggered (for example an emergency stop, demand response or external switch).
Likely causes:
- Emergency stop or external shutdown switch operated
- Network/demand response command
- Wiring fault on the control input (if nobody operated a switch)
What you can safely do:
- Check whether anyone operated an emergency stop or shutdown switch on purpose
- If so, follow the manual to release it only when it is safe
- If nobody did, call us
Warning 205PV1 or PV2 boost brokenFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 207USB over-currentInfo
What it means: A monitoring or communication accessory (Wi-Fi/4G/data logger, display or clock) is reporting a problem. This usually doesn't stop the system generating.
Likely causes:
- Home Wi-Fi router changed, moved or restarted
- Weak Wi-Fi or mobile signal at the inverter
- Monitoring module or SIM/data issue
What you can safely do:
- Restart your home router and check it reaches the inverter location
- If you changed router or Wi-Fi password, the dongle needs reconfiguring (see the manufacturer's app guide or ask us)
- If generation looks normal but the alarm persists, call us
Warning 401Inverter communicates with Meter abnormalWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 404EEPROM abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 405Firmware version is not consistentFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Error 402Output High DCIFault
What it means: The inverter detected too much DC current in its AC output, which the grid standards don't allow, so it disconnected.
Likely causes:
- A one-off disturbance (if it is occasional)
- Internal measuring or power stage problem (if it repeats)
What you can safely do:
- If it happened once and the system recovered, keep an eye on it
- If it repeats, call us
Error 404Bus sample faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 405Relay faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 408Over TemperatureWarning
What it means: The inverter is running too hot, so it has reduced output or paused to protect itself.
Likely causes:
- High ambient temperature or direct afternoon sun on the inverter
- Blocked air vents or heat sink (dust, cobwebs, stored items)
- A fan problem (on fan-cooled models)
What you can safely do:
- Make sure nothing is stacked against or in front of the inverter, and leave the manufacturer's clearances around it
- Gently clear dust or leaves from the outside of the vents, without opening the unit or spraying water
- Let it cool. It normally resumes by itself
- If it keeps happening on mild days, call us
Error 409Bus over voltageFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 411DSP communicates with M3 abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 414EEPROM faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 417DSP and redundant M3 sampled data differFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 420GFCI faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 200AFCI fault (listed in MIC TL-X manual)Safety-critical
What it means: The inverter's arc-fault detection has picked up a pattern that looks like electrical arcing on the DC (solar) side, which can be a fire risk. The inverter shuts down DC power flow as a precaution.
Likely causes:
- Loose or poorly crimped DC connector
- Damaged DC cable
- Water or corrosion in a DC connector or isolator
What you can safely do:
- Do not reset it repeatedly and do not touch DC cables or isolators
- If you see smoke or flames or smell burning, keep clear and call 000
- Call us or a licensed electrician to inspect the DC wiring before the system is restarted
Error 425AFCI self-test fault (listed in MIC TL-X manual)Fault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
MOD TL3-X (three-phase) (63 codes)
Warning 200String faultWarning
What it means: One solar string is behaving differently from the others (lower output or current flowing the wrong way), which often points to a panel, connector or configuration issue.
Likely causes:
- Shading or heavy dirt on part of the array
- Different panel counts or orientations on strings sharing an input
- Faulty panel, connector or cable
What you can safely do:
- From the ground, check for new shading (trees, new structures) or obvious debris
- Compare string readings in your monitoring app if available
- Book a service check if it continues
Warning 201String PID quick-connect terminal detection errorFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 202DC SPD function abnormalFault
What it means: A surge protection device (SPD) inside or connected to the inverter is reporting a fault, often after a lightning storm or grid surge.
Likely causes:
- SPD has done its job after a surge and now needs replacing
- SPD wiring fault
What you can safely do:
- Don't open the inverter
- Call us. SPDs must be replaced by a licensed electrician
Warning 203PV circuit shortFault
What it means: A solar string or the battery appears to be connected with positive and negative swapped.
Likely causes:
- Polarity error during installation or maintenance
What you can safely do:
- Do not touch any DC wiring
- Call us or a licensed electrician
Warning 204Dry contact function abnormalInfo
What it means: The system has received a shutdown or control signal, or a protective input has been triggered (for example an emergency stop, demand response or external switch).
Likely causes:
- Emergency stop or external shutdown switch operated
- Network/demand response command
- Wiring fault on the control input (if nobody operated a switch)
What you can safely do:
- Check whether anyone operated an emergency stop or shutdown switch on purpose
- If so, follow the manual to release it only when it is safe
- If nobody did, call us
Warning 205PV boost driver brokenFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 206AC SPD function abnormalFault
What it means: A surge protection device (SPD) inside or connected to the inverter is reporting a fault, often after a lightning storm or grid surge.
Likely causes:
- SPD has done its job after a surge and now needs replacing
- SPD wiring fault
What you can safely do:
- Don't open the inverter
- Call us. SPDs must be replaced by a licensed electrician
Warning 207USB (U disk) over-current protectionInfo
What it means: A monitoring or communication accessory (Wi-Fi/4G/data logger, display or clock) is reporting a problem. This usually doesn't stop the system generating.
Likely causes:
- Home Wi-Fi router changed, moved or restarted
- Weak Wi-Fi or mobile signal at the inverter
- Monitoring module or SIM/data issue
What you can safely do:
- Restart your home router and check it reaches the inverter location
- If you changed router or Wi-Fi password, the dongle needs reconfiguring (see the manufacturer's app guide or ask us)
- If generation looks normal but the alarm persists, call us
Warning 208DC fuse openFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 209DC input voltage exceeds maximumFault
What it means: The DC voltage coming from the solar panels is higher than the inverter is rated for. Over-voltage can damage the inverter.
Likely causes:
- Too many panels wired in series in a string (system design/installation issue)
- Very cold, bright mornings raise panel voltage
- Incorrect panel or string configuration after a change to the system
What you can safely do:
- Do not touch the DC isolator or cables unless the manufacturer's owner shutdown tells you to
- Call us. The string design needs to be checked by a licensed installer
Warning 210PV reversedFault
What it means: A solar string or the battery appears to be connected with positive and negative swapped.
Likely causes:
- Polarity error during installation or maintenance
What you can safely do:
- Do not touch any DC wiring
- Call us or a licensed electrician
Warning 300No utilityWarning
What it means: The inverter cannot see a normal mains supply, so it has stopped exporting to the grid (and a hybrid system may switch to backup).
Likely causes:
- Power outage in your street or area
- A tripped or switched-off solar/inverter circuit breaker in the switchboard
- Loose AC connection between the switchboard and the inverter
What you can safely do:
- Check whether the rest of the house (or your neighbours) has power, and check your network operator's outage map
- Check the switchboard for a tripped solar supply main switch or inverter breaker. Only reset it once. If it trips again, leave it off and call an electrician
- Wait. Once normal grid power is back, the inverter normally reconnects by itself after its safety checks (often a few minutes)
- If grid power is normal but the alarm stays, call us
Warning 301Grid voltage out of rangeWarning
What it means: The mains voltage the inverter measured was outside the limits allowed for your network, so it disconnected or reduced output to protect the grid. This is usually a grid condition, not a faulty inverter.
Likely causes:
- High street voltage, common on sunny afternoons when many homes export solar
- Grid disturbances or voltage dips
- Long or undersized AC cabling between the inverter and the switchboard (installation issue)
- Grid protection settings that don't match your network's requirements
What you can safely do:
- Wait. The inverter reconnects by itself once voltage is back within limits
- Note the time of day it happens. If it happens most sunny days, tell us, because it may need a voltage check or a report to your network operator
- Don't try to change grid protection settings yourself. In Australia they are set to AS/NZS 4777.2 and your network operator's requirements
Warning 302Grid frequency out of rangeWarning
What it means: Grid frequency moved outside the allowed range, so the inverter disconnected or reduced output as the standards require.
Likely causes:
- Short grid disturbance
- Running on a generator or a weak supply
- Grid settings that don't match the local network
What you can safely do:
- Wait for automatic reconnection
- If it happens often, record the times and contact us
Warning 303EPS mode overloadWarning
What it means: The backup/EPS (off-grid) output is overloaded or abnormal, so the system has limited or switched off backup power.
Likely causes:
- Too many or too large appliances on backup circuits during an outage (for example ovens, air conditioners, pumps)
- High start-up surge from motors or compressors
- A short circuit on a backup circuit
What you can safely do:
- Switch off large appliances on backup circuits
- Wait for the system to retry (some models lock out for a period after repeated overloads)
- If it trips with only small loads on, or you suspect a short circuit, call an electrician
Warning 304CT open or wrongWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 305CT line reversed or ground failWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 306Communication fault: M3 didn't receive SP-CT dataWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 307Communication faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 400Fan function abnormalWarning
What it means: A cooling fan isn't working properly, which can make the unit run hot and reduce output.
Likely causes:
- Fan blocked by debris
- Fan worn or failed
- Fan wiring fault
What you can safely do:
- From outside, check that nothing is blocking the vents
- Don't open the unit
- Call us to arrange a fan check or replacement
Warning 401Meter abnormalWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Warning 402Optimiser and inverter communication abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 403String communication abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 404EEPROM abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Warning 405DSP and COM firmware version unmatchFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Warning 406Boost module errorFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 200AFCI faultSafety-critical
What it means: The inverter's arc-fault detection has picked up a pattern that looks like electrical arcing on the DC (solar) side, which can be a fire risk. The inverter shuts down DC power flow as a precaution.
Likely causes:
- Loose or poorly crimped DC connector
- Damaged DC cable
- Water or corrosion in a DC connector or isolator
What you can safely do:
- Do not reset it repeatedly and do not touch DC cables or isolators
- If you see smoke or flames or smell burning, keep clear and call 000
- Call us or a licensed electrician to inspect the DC wiring before the system is restarted
Error 201Leakage current too highSafety-critical
What it means: The inverter measured leakage (residual) current flowing to earth above its safety limit and disconnected. This can indicate damaged insulation somewhere in the system.
Likely causes:
- Damaged DC or AC cable insulation
- Moisture in connectors or equipment
- A one-off disturbance (if it happens once and never again)
What you can safely do:
- Don't touch cabling or equipment
- If it happens repeatedly, or together with an insulation/isolation alarm, call an electrician or us promptly
Error 202DC input voltage exceeds maximumFault
What it means: The DC voltage coming from the solar panels is higher than the inverter is rated for. Over-voltage can damage the inverter.
Likely causes:
- Too many panels wired in series in a string (system design/installation issue)
- Very cold, bright mornings raise panel voltage
- Incorrect panel or string configuration after a change to the system
What you can safely do:
- Do not touch the DC isolator or cables unless the manufacturer's owner shutdown tells you to
- Call us. The string design needs to be checked by a licensed installer
Error 203PV isolation lowSafety-critical
What it means: The inverter measured low insulation resistance between the solar/battery DC circuits and earth. In Australia this is treated as an earth fault alarm, and the system must be checked by a licensed electrician.
Likely causes:
- Damaged DC cable insulation (for example from rodents, UV or a pinched cable)
- Water in a DC connector, isolator or junction box
- A damaged solar panel or backsheet
- Heavy dew or rain can trigger it temporarily on marginal systems
What you can safely do:
- Do not touch panels, DC cables, rooftop isolators or the inverter's DC connectors
- If it clears by itself after the weather dries out, still report it, because repeated alarms point to a developing fault
- Book an electrician or call us. An insulation test needs specialist equipment
- If you see smoke, burn marks or smell burning, keep clear and call 000
Error 300AC V OutrangeWarning
What it means: The mains voltage the inverter measured was outside the limits allowed for your network, so it disconnected or reduced output to protect the grid. This is usually a grid condition, not a faulty inverter.
Likely causes:
- High street voltage, common on sunny afternoons when many homes export solar
- Grid disturbances or voltage dips
- Long or undersized AC cabling between the inverter and the switchboard (installation issue)
- Grid protection settings that don't match your network's requirements
What you can safely do:
- Wait. The inverter reconnects by itself once voltage is back within limits
- Note the time of day it happens. If it happens most sunny days, tell us, because it may need a voltage check or a report to your network operator
- Don't try to change grid protection settings yourself. In Australia they are set to AS/NZS 4777.2 and your network operator's requirements
Error 301AC terminals reversedFault
What it means: The inverter has detected an AC wiring problem, for example active and neutral swapped or a connection made the wrong way round.
Likely causes:
- AC wiring error at installation or after other electrical work
- Wiring on the meter or CT the wrong way round
What you can safely do:
- Do not touch any wiring
- Leave the system as it is and book a licensed electrician (or call us)
Error 302No AC connectionWarning
What it means: The inverter cannot see a normal mains supply, so it has stopped exporting to the grid (and a hybrid system may switch to backup).
Likely causes:
- Power outage in your street or area
- A tripped or switched-off solar/inverter circuit breaker in the switchboard
- Loose AC connection between the switchboard and the inverter
What you can safely do:
- Check whether the rest of the house (or your neighbours) has power, and check your network operator's outage map
- Check the switchboard for a tripped solar supply main switch or inverter breaker. Only reset it once. If it trips again, leave it off and call an electrician
- Wait. Once normal grid power is back, the inverter normally reconnects by itself after its safety checks (often a few minutes)
- If grid power is normal but the alarm stays, call us
Error 303NE abnormalSafety-critical
What it means: The inverter detected a problem with the earth (protective earth/PE) or with the neutral-to-earth connection. A sound earth is essential for electrical safety.
Likely causes:
- Loose or missing earth connection on the inverter or array
- Neutral and earth problem in the AC wiring or switchboard
- Fault in the building's main earth
What you can safely do:
- Do not touch the inverter, frames or cabling
- Leave the system off if it has shut down. Call a licensed electrician or us to test the earthing
Error 304AC F OutrangeWarning
What it means: Grid frequency moved outside the allowed range, so the inverter disconnected or reduced output as the standards require.
Likely causes:
- Short grid disturbance
- Running on a generator or a weak supply
- Grid settings that don't match the local network
What you can safely do:
- Wait for automatic reconnection
- If it happens often, record the times and contact us
Error 305Overload faultWarning
What it means: The backup/EPS (off-grid) output is overloaded or abnormal, so the system has limited or switched off backup power.
Likely causes:
- Too many or too large appliances on backup circuits during an outage (for example ovens, air conditioners, pumps)
- High start-up surge from motors or compressors
- A short circuit on a backup circuit
What you can safely do:
- Switch off large appliances on backup circuits
- Wait for the system to retry (some models lock out for a period after repeated overloads)
- If it trips with only small loads on, or you suspect a short circuit, call an electrician
Error 306CT LN reversedWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Error 307Communication fault: M3 didn't receive SP-CT dataWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Error 308Communication fault: pairing time too longWarning
What it means: The inverter isn't getting correct readings from its energy meter or current sensor (CT). This affects export limiting, battery charging and monitoring accuracy.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Error 400DCI bias abnormalFault
What it means: The inverter detected too much DC current in its AC output, which the grid standards don't allow, so it disconnected.
Likely causes:
- A one-off disturbance (if it is occasional)
- Internal measuring or power stage problem (if it repeats)
What you can safely do:
- If it happened once and the system recovered, keep an eye on it
- If it repeats, call us
Error 401DC voltage high faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 402Output DC current too highFault
What it means: The inverter detected too much DC current in its AC output, which the grid standards don't allow, so it disconnected.
Likely causes:
- A one-off disturbance (if it is occasional)
- Internal measuring or power stage problem (if it repeats)
What you can safely do:
- If it happened once and the system recovered, keep an eye on it
- If it repeats, call us
Error 403Output current unbalanceFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 404Bus sample faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 405Relay faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 406Init model faultFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Error 407Auto test failureFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 408NTC temperature too highWarning
What it means: The inverter is running too hot, so it has reduced output or paused to protect itself.
Likely causes:
- High ambient temperature or direct afternoon sun on the inverter
- Blocked air vents or heat sink (dust, cobwebs, stored items)
- A fan problem (on fan-cooled models)
What you can safely do:
- Make sure nothing is stacked against or in front of the inverter, and leave the manufacturer's clearances around it
- Gently clear dust or leaves from the outside of the vents, without opening the unit or spraying water
- Let it cool. It normally resumes by itself
- If it keeps happening on mild days, call us
Error 409Bus voltage abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 410Communication board / control panel battery-voltage sampling inconsistentFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 411Communication faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 412Temperature sensor connection abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 413IGBT drive faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 414EEPROM faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 415Internal power test fail (PV power low)Fault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 416Overcurrent protected by softwareFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 417Grid voltage sampling inconsistentFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 418DSP and COM firmware version unmatchFault
What it means: There is a firmware, model or configuration mismatch between parts of the system, so it can't run normally.
Likely causes:
- Interrupted or partial firmware update
- Parts replaced with different firmware versions
- Incorrect model or country/region setting
What you can safely do:
- Don't try to reflash firmware yourself unless the manufacturer's app tells you to and it's an owner function
- Call us. We can arrange a firmware update or reconfiguration with the manufacturer
Error 419Inconsistent leakage current samplingFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 420GFCI module damageFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 421CPLD abnormalFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 422Sampling inconsistentFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Error 425AFCI self-test faultFault
What it means: The equipment's self-checks found an internal problem (for example relays, measuring circuits, internal communication or power electronics). Some of these clear by themselves after a one-off event, but repeated alarms usually need a technician.
Likely causes:
- A one-off disturbance (for example a grid event)
- Internal component or circuit board fault
- Firmware issue
What you can safely do:
- Note the code, time and whether it clears by itself
- If your installer showed you the owner shutdown/restart procedure from the manufacturer's manual (summarised at the top of this page), you may restart the system once. Do not open covers or touch cabling.
- If the code returns or the system stays offline, call us. Internal faults are a warranty/technician job
Growatt Australia Helpdesk articles (MIC/MIN/MOD/SPH with smart meter) (4 codes)
Warn 304CT Open (MIN 7000-10000TL-X with cable CT)Warning
What it means: On MIN 7-10k TL-X inverters that use a cable CT for export limiting, the inverter isn't getting a valid CT signal. Growatt says this warning was removed in DSP firmware AMAA04xx and later, and recommends a smart meter instead of a cable CT.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Source: Growatt Australia Helpdesk: Warn code 304 (CT Open), updated 2025-03-04
Warn 308Meter OpenWarning
What it means: The readings coming from the smart meter aren't changing, which usually means the CT clamp isn't on the right cable or the meter link has a problem.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Source: Growatt Australia Helpdesk: Warn code 308 (Meter Open), updated 2025-03-04
Warn 309Meter ReverseWarning
What it means: The meter reports more export than the inverter is producing. Typical causes are a CT clamp or meter wiring the wrong way round, or another inverter on site.
Likely causes:
- CT clamp facing the wrong way or its two wires swapped
- Meter active/neutral swapped
- More than one inverter on site (can trigger this legitimately)
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Source: Growatt Australia Helpdesk: Warn code 309 (Meter Reverse), updated 2025-03-04
Warn 401Meter communication (no data from meter)Warning
What it means: Export limiting or power sensing is switched on, but the inverter receives no data from the smart meter.
Likely causes:
- Meter or CT communication cable loose or damaged
- CT clamp fitted on the wrong cable or the wrong way round
- Meter has lost power or is faulty
What you can safely do:
- Check the app. Generation may still be running normally
- Don't open the switchboard
- Call us to check the meter/CT wiring. If your system has an export limit, this needs fixing promptly
Source: Growatt Australia Helpdesk: Warn code 401, updated 2025-03-04
SPM 8000-10000TL-HU hybrid (Helpdesk troubleshooting guide) (2 codes)
Error 69 (at start-up)Start-up error 69 after a shutdownInfo
What it means: Growatt Australia says that when an SPM restarts some time after a normal shutdown, it may briefly show start-up error 69, which normally clears by itself after about 10 minutes.
Likely causes:
- Normal behaviour when restarting after a shutdown
What you can safely do:
- Wait about 10 minutes for it to clear
- If it does not clear, call us
Source: Growatt Australia Helpdesk: Troubleshooting Guide for SPM Inverters, updated 2026-03-02
Error 90 (at start-up)Start-up error 90 after a shutdownInfo
What it means: Growatt Australia says that when an SPM restarts some time after a normal shutdown, it may briefly show start-up error 90, which normally clears by itself after about 10 minutes.
Likely causes:
- Normal behaviour when restarting after a shutdown
What you can safely do:
- Wait about 10 minutes for it to clear
- If it does not clear, call us
Source: Growatt Australia Helpdesk: Troubleshooting Guide for SPM Inverters, updated 2026-03-02
Manufacturer support contacts
| Contact | Phone | Email / channel |
|---|---|---|
| Growatt New Energy Australia, Engineering Support Hotline (website) | 1800 476 928 | australia@growatt.com |
If Total Solar installed your system, contact us first.
Need help with a fault code?
Book a service call with our licensed electricians, or call us to talk it through. Have your fault code and a photo of the screen or app ready.