P0DB1Hybrid/EV Battery Cell Balancing Circuit B Stuck On
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0DB1: in circuit B the bleed path stays closed even after the controller withdrew the command. The cells of group B are drained without pause, so their voltage falls behind the others, worst during long standstill. Detection usually compares commanded and reported switch state; GM's eAssist logic for a related code needs 7 failed of 10 samples before a Type B entry. Toshiba describes a comparator check that spots a shorted balancing switch while it should be off. Ford names P0DB1 for its hybrid BECM; the 2015 OBD summary flags it when, at start-up with open contactors, one of the six cells served by circuit B differs from the pack mean by more than 75 mV. The electrical fault of the same circuit is P0DB0, the opposite stuck state P0DB2.
- What you may notice
- MIL with battery warning
- Group B cells clearly low after parking
- Usable charge and range shrinking
- Likely causes
- LikelyShorted balancing transistor in circuit B
- PossibleDrive output of the monitoring chip stuck active
- RareMoisture or contamination on the module board creating a leakage path
- 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.