P2BC9Battery Charging System Positive Contactor B Control Circuit Low
- Generic OBD-II code · Powertrain
- How the car detects it
- P2BC9 is the low-signal fault on the coil feed of plus-side charging contactor B: the module measures less voltage on that wire than its command calls for, most often because the wire touches ground or the output stage is being dragged down. With a high-side feed the coil is then starved and the contactor never pulls in, or the output stage trips its own protection. No manufacturer documents P2BC9 publicly. GM notes for its corresponding contactor A test on the Chevrolet Volt (P0D0A) that the open-circuit check cannot detect a short to ground, so this case needs a check of its own. CARB requires monitoring of the charging system on plug-in vehicles. Expect insulation rubbed through on the battery casing or moisture inside a plug. P2BCA is the high counterpart, P2BD0 the same fault on the minus side. That charging mode is then refused.
- What you may notice
- Charging session does not start
- Charging fault message
- Likely causes
- LikelyControl wire of contactor B shorted to ground
- PossibleMoisture or corrosion in a connector
- RareCoil of contactor B internally shorted
- 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.