OBD-II code · Powertrain (generic)
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.
Is it safe to drive with P0B29?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyCells in group aged - capacity reduced
- PossibleDeep discharge event
- Less likelyPack cell imbalance approaching service threshold
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 3–16 h
- Emissions test
- Usually unaffected
- Parts involved
- Hv Battery B, Bms
Related codes
- P0B25Hybrid/EV Battery A Voltage Low
- P0B2DHybrid/EV Battery C Voltage Low
- P0B31Hybrid/EV Battery D Voltage Low
- P0B26Hybrid/EV Battery A Voltage High
- P0B27Hybrid/EV Battery B Voltage
- P0B28Hybrid/EV Battery B Voltage Unstable
- P0B2AHybrid/EV Battery B Voltage High
- P0B2BHybrid/EV Battery C Voltage
- P0B2CHybrid/EV Battery C Voltage Unstable
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.