P2BC5 code meaning
Battery Charging System Positive Contactor B Stuck Closed
What P2BC5 means
P2BC5 reports that positive charging contactor B still conducts after the open command, normally because its contacts have fused. Mercedes-Benz stores it, often with P2BCC, in the DC charge connection unit (N116/5, on the eSprinter N24/6) of GLE, E- and S-Class plug-in hybrids, the EQB and the eSprinter; after a DC session the vehicle refuses to start. Bulletin LI47.70-P-079912 blames current ripple, overcurrent or overvoltage from the station and contacts that part too late, and prescribes a software update plus a contactor-fault reset rather than a new unit. Mazda lists it as OBC contactor (+) stuck on in CX-90 (from 2024) and CX-70 (from 2025) plug-in hybrids and swaps Junction Box No. 2 (30-003-26). The reverse fault is P2BC6, the minus side P2BCC.
P2BC5 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 10 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2BC5
- Vehicle will not start after DC charging (Mercedes)
- High-voltage or hybrid system warning in the cluster
- Further charging blocked
Common causes of P2BC5
- Most likelyContacts of positive contactor B welded, e.g. after current peaks at the end of charging
- PossibleSoftware of the charging module judges the contactor state wrongly (Mercedes update)
- PossibleRipple, overcurrent or overvoltage from the charging station
- Less likelyCoil driver does not switch off
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bcs pos contactor bWiring harnessBms
What each part of P2BC5 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| C5 | The exact fault in that area. |
What to do next
- Note P2BC5 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2BC5
What does P2BC5 mean?
P2BC5 means "Battery Charging System Positive Contactor B Stuck Closed". P2BC5 reports that positive charging contactor B still conducts after the open command, normally because its contacts have fused. It is a generic code, so it means the same on every make.
Is it safe to drive with P2BC5?
Drive gently and only to a workshop. With P2BC5 the car can go into limp mode (reduced power) to protect itself.
Will P2BC5 fail an emissions test?
P2BC5 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P2BC5 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 10 hours of work. This is a job for a workshop.
Will P2BC5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.