P2BC4Battery Charging System Positive Contactor B Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- P2BC4 is the catch-all electrical code for positive contactor B of the charging system, the second charging switch on the plus side next to contactor A (P0D07). Which charging path B serves is up to the maker: Mercedes-Benz files its B codes under the DC charge connection unit of its plug-in hybrids, EQB and eSprinter, Mazda under the on-board charger branch of its two large plug-in SUVs, and Audi calls it charging contactor 2 on the Q8 e-tron. No manufacturer documents P2BC4 itself publicly. Under CARB the charging system of plug-in vehicles has to be supervised, and a GM patent judges such contactors by their coil current. Fused or non-closing contacts are P2BC5/P2BC6, driver faults P2BC7–P2BCA, the minus side P2BCB. Usually only the affected charging mode is lost.
- What you may notice
- DC fast charging or on-board charger charging (depending on design) refused
- Charging fault message in the cluster or app
- Driving usually still possible
- Likely causes
- PossibleCoil of positive contactor B open or shorted
- PossibleWiring or connector fault in the contactor B branch
- RareFault or software issue in the controlling module
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.