OBD-II code · Powertrain (generic)
P0B27 Hybrid/EV Battery B Voltage
The BMS detects a generic fault on the voltage measurement of HV battery B. Cell-group voltage monitoring is the foundation of HV battery safety — drift here triggers contactor opening, charge inhibit, and reduced power to protect the pack.
Is it safe to drive with P0B27?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyCell imbalance in this group
- PossibleSense circuit fault
- Less likelyGround point with elevated resistance
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
- P0B23Hybrid/EV Battery A Voltage
- P0B2BHybrid/EV Battery C Voltage
- P0B2FHybrid/EV Battery D Voltage
- P0B24Hybrid/EV Battery A Voltage Unstable
- P0B25Hybrid/EV Battery A Voltage Low
- P0B26Hybrid/EV Battery A Voltage High
- P0B28Hybrid/EV Battery B Voltage Unstable
- P0B29Hybrid/EV Battery B Voltage Low
- P0B2AHybrid/EV Battery B Voltage High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.