BYD "Please check the OBC system" charging warning
What the "Please check the OBC system" dashboard message means on BYD EV and DM-i models, and what is safe to do before calling for service.
Safety and service note
What this means
"Please check the OBC system" refers to the on-board charger, the component that converts AC power from a wall socket or public AC charge point into DC power the battery can store. According to the official BYD owner's handbook, this message means the on-board charging system is faulty. It typically appears while charging, not while driving.
What causes it
The handbook's own guidance is to check the charging connection first: a connector that is not fully seated, a faulty charging cable, or an issue at the AC charge point itself can all trigger this message even when the on-board charger is fine. Reconnecting the charging equipment resolves many cases.
What to do
Stop charging, disconnect, and re-connect the charging cable or connector, making sure it is fully seated at both the vehicle and the wall/charge-point end. If the message persists after reconnecting, contact a BYD authorised dealer or service provider -- do not attempt to open or inspect the on-board charger yourself, as it is part of the vehicle's high-voltage charging system.
Important
Stop charging, disconnect, and re-connect the charging cable or connector, making sure it is fully seated at both the vehicle and the wall/charge-point end. If the message persists after reconnecting, contact a BYD authorised dealer or service provider -- do not attempt to open or inspect the on-board charger yourself, as it is part of the vehicle's high-voltage charging system.
Frequently asked questions
What is the OBC on a BYD?
OBC stands for on-board charger, the component that converts AC power from a wall socket or public charger into DC power the battery stores.
Can I keep charging with this message showing?
Disconnect and reconnect the charging equipment first, as the official handbook recommends; if the message returns, stop and contact BYD service rather than continuing to charge.
Is this the same as a home wallbox fault?
Not necessarily -- the message can be triggered by a poor connection at the charge point as well as by the vehicle's own on-board charger, which is why reconnecting is the first step.
Does this affect DC fast charging too?
The on-board charger is used for AC charging; DC fast charging bypasses it, so a DC-specific fault would show a different message.
Is this safe to diagnose myself?
No. The on-board charger is part of the high-voltage charging system, so beyond checking the physical connection, diagnosis and repair should be left to an authorised BYD technician.
Does this message appear on other BYD models?
Yes -- it is a shared instrument-cluster fault prompt across BYD's EV and DM-i range; for example, BYD Sealion 5 DM-i has its own dedicated warning-lights guide covering the same charging-system messages.
Sources for this guide
This guide is for informational purposes only. Always consult an authorised service centre for safety-critical repairs. AutoTechHelp is not liable for any damage resulting from the use of this information.