P0B29
Hybrid/EV Battery B Voltage Low
The voltage of HV battery B is below the expected window. Cell-group depleted, deeply aged, or sense fault.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Common causes
Ordered by how often each turns out to be the cause.
- Cells in group aged - capacity reducedCommon
- Deep discharge eventPossible
- Pack cell imbalance approaching service thresholdLess likely
Parts involved
- Hv Battery B
- Bms
P0B29 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.