P2BCFBattery Charging System Negative Contactor B Control Circuit Range/Performance
- Generic OBD-II code · Powertrain
- How the car detects it
- P2BCF points to a control circuit on negative charging contactor B that is neither open nor shorted yet still implausible: coil current, line voltage or switching time fall outside the window that belongs to the commanded state. No manufacturer documents P2BCF publicly, and no published GM table has such a check for a charging contactor coil. CARB asks for rationality checks in addition to circuit checks on plug-in charging components. GM's patent on diagnosing the battery disconnect unit shows the kind of evidence available: how the coil current rises after a brief pulse, held against a stored profile, separates a healthy contactor from a sluggish one. A shifted coil resistance, corrosion in the connector and a poor module ground are typical. Opens are P2BCE, low and high P2BD0/P2BD1, the plus side P2BC8.
- What you may notice
- Charging drops out or will not begin
- Charging fault message from time to time
- Likely causes
- LikelyCorrosion or contact resistance in the control connector
- PossibleCoil resistance of negative contactor B shifted
- RarePoor ground of the controlling module
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.