What it means
The positive contactor B of the battery charging system reports a control circuit range/performance 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’s low-voltage control circuit operates the switch that connects the high-voltage charging path. P2BC8 sets when the circuit response is outside the expected range or performance window, even if it is not a clear open or short.
Common causes
Most likely first.
- Coil resistance drifted
- High-resistance contact in connector
- Sensor element aged beyond calibration window
Symptoms
- Hybrid-system warning light or message
- Charging may be limited or unavailable
- Reduced hybrid power
How to diagnose it
- Record freeze-frame data and review commanded versus reported contactor B status to identify the conditions when its control response falls out of range.
- Inspect the low-voltage connector and harness for corrosion, loose terminals, or other resistance-adding damage.
- Check the control circuit and coil resistance using the manufacturer’s procedure and compare the results with its specification.
- Inspect related hybrid-system codes and verify the low-voltage supply and ground to the contactor control circuit.
- After correcting the circuit fault, clear the code and verify contactor operation through the manufacturer’s diagnostic routine.
Common fixes
- Clean or repair a high-resistance connector contact in contactor B’s control circuit.
- Repair a damaged control wire or poor ground affecting the circuit response.
- Replace positive contactor B if its coil or response remains outside specification.
Can I keep driving?
Limit driving if hybrid power is reduced or charging is limited, and avoid relying on the vehicle for a trip if READY operation is unreliable. Have the high-voltage contactor system checked by a qualified technician.
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.