P2BCCBattery Charging System Negative Contactor B Stuck Closed
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- How the car detects it
- P2BCC says negative charging contactor B is still closed although the module ordered it open – in practice fused contacts on the return side. Mercedes-Benz lists it in the DC charge connection unit next to P2BC5 and P0E8929 (DC input current too high); the plug-in hybrid, EQB or eSprinter then cannot be started after DC charging. The bulletins name ripple and overvoltage from the station and contacts that open too late, and call for a software update and a contactor-fault reset instead of a new unit. Mazda names it OBC contactor (−) stuck on in the same bulletin and also prescribes a new Junction Box No. 2. Hyundai and Toyota patents find such welding by opening one pole while the other stays closed and checking the voltage behind it. P2BC5 is the plus side, P2BCD the reverse fault.
- What you may notice
- Vehicle will not start after DC charging (Mercedes)
- High-voltage system warning
- Charging blocked
- Likely causes
- LikelyContacts of negative contactor B welded at the end of charging
- PossibleCharging module software (Mercedes update)
- PossibleCurrent ripple or overvoltage from the DC station
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.