What it means
The positive contactor B of the battery charging system reports a stuck closed condition. HV charging path cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Positive contactor B switches part of the high-voltage battery charging path on command. P2BC5 sets when the system detects that this contactor remains electrically closed when it should be open, so the charging path cannot be controlled as expected.
Common causes
Most likely first.
- Contactor contacts welded closed
- Output driver stuck on
- Carbon or debris buildup preventing free movement
Symptoms
- Hybrid-system warning light or message
- Vehicle may not enter READY mode
- Charging may be unavailable
How to diagnose it
- Save freeze-frame data and review contactor B’s commanded state and reported state to confirm that the fault is a closed-state mismatch.
- Check other hybrid-system codes and the event sequence for a control-driver fault that could be holding the contactor on.
- With the high-voltage system safely disabled using the manufacturer’s procedure, inspect the accessible low-voltage connector and harness for damage, contamination, or poor contact.
- Have a qualified technician test the contactor and its output driver using the manufacturer’s isolation and diagnostic procedure; avoid directly testing high-voltage terminals.
- After repair, verify that contactor B opens and closes only when commanded and confirm charging and READY operation.
Common fixes
- Repair a control-wire or connector fault that is keeping the contactor commanded on.
- Replace positive contactor B if its contacts remain closed when the manufacturer’s test calls for it to open.
- Repair or replace the contactor output driver if testing confirms it is stuck on.
Can I keep driving?
A contactor that will not open can prevent safe control of the high-voltage charging path, so do not continue driving or attempt to charge the vehicle if the hybrid warning is present. Arrange qualified hybrid-system service or recovery.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.