P0DB2Hybrid/EV Battery Cell Balancing Circuit B Stuck Off
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Stuck off on circuit B (P0DB2) is the passive failure: the command arrives, but the bleed resistor of that group carries no current, so its high cells are never trimmed. LG Chem's patent EP2730933A1 tests for this by switching the balancing circuit on and off and watching how the voltage across a diagnosis resistor reacts; no change means a dead circuit. The result builds up over many charges: cells of group B reach the upper limit first and end charging early, while the rest stay below. CARB 13 CCR 1968.2 counts this as a balancing malfunction. Ford lists P0DB2 in its 2016 hybrid OBD summary: the BECM bleeds only the highest cells down to the others and judges each six-cell circuit once per power-up against a 75 mV limit. Compare P0DB1 for the opposite fault.
- What you may notice
- MIL and battery warning
- Charging stops before the expected state of charge
- High cell voltages in group B in live data
- Likely causes
- LikelyBleed resistor of group B burnt open
- PossibleBalancing transistor of circuit B no longer switching
- RareOpen terminal or cell tap connection in group B
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €300 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.