BYD error codes explained

Abnormal shutdown (open panel) / PreCharge failure / DC reverse connection.

What you can do

• Do not touch the DC isolators, cables or connectors
• Call your installer - this points to a wiring problem that needs a licensed electrician

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Voltage Sensor Failure / BMU<>BMS communication failure.

What you can do

• Check the app - the battery may show as offline or with no state of charge
• Restart the system once using the shutdown and start-up steps in your owner's manual (battery last off, first on, unless your manual says otherwise)
• If the alarm comes back, call your installer - battery communication cables must be checked by them

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Faulty temperature sensor.

What you can do

• Check from a safe distance that the inverter is shaded, has clear space around it and that nothing is blocking the vents
• It usually recovers once it cools down
• If it repeats often or you can hear a noisy/failed fan, call your installer

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PackVoltage Sensor Failure.

What you can do

• This is usually caused by the mains supply, not the solar system
• The inverter normally reconnects by itself once grid voltage is back in range
• If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed

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Incorrect module quantity / Module not detected. EC 303

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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- Make sure app-configuration has been completed correctly (especially module type and

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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quantity!). EC 603

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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- EC 203 to EC 803 means that a module is not recognized. The first number (= number of

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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white flashes) indicates which module is probably affected. This module, or the module above it, can be responsible for the event code. Example: EC 203 = second module from the top / EC 403 = fourth-top module.

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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Current Sensor Failure.

What you can do

• Note the code, then restart the system once using the owner shutdown/start-up steps in your manual
• If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer

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Undervoltage.

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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PreCharge Fault.

What you can do

• Note the code, then restart the system once using the owner shutdown/start-up steps in your manual
• If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer

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Make sure that the latest firmware is installed and that the battery has been properly restarted. If the problem remains: it is Probably caused by a module. Follow the “Module exclusion method” (see Section 2.11).

What you can do

• Check the battery status and any extra alarms in the app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If the alarm comes back, or the battery is hot, swollen, noisy or smells, keep clear and call your installer

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Low voltage. The system needs to charge very soon and should not be further discharged! 1. Shut down the system quickly to avoid further discharge. Check whether the system can shut down normally (by pressing the LED button for 5s).

What you can do

• Note the code, date and time and check the monitoring app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If it comes back, call your installer

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Normal when the battery has just started. LED will turn to solid white when:

What you can do

• Check the battery status and any extra alarms in the app
• Restart the system once using the owner shutdown/start-up steps in your manual if it allows
• If the alarm comes back, or the battery is hot, swollen, noisy or smells, keep clear and call your installer

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No communication with inverter. Check inverter communication (Section 2.4) 12 2.10 Voltage measurement and undervoltage ATTENTION: High voltage! You can see the max. and min. cell voltage in the BeConnect App. You can also get the detailed module and cell voltage in the BCP Program (section 2.8) or measure it manually according to the below description: Measurement of Tower Voltage Take down the BCU and measure the tower voltage on the topmost module as shown below. Note: The nominal voltage should be module quantity times 100V (for HVS) or module quantity times 50V (for HVM). If the measured

What you can do

• Check that your home Wi-Fi/internet is working and restart your router
• Wait an hour - monitoring often reconnects by itself
• If the inverter screen also shows a fault, or the alarm stays for more than a day, call your installer

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