P0A27
Hybrid/EV Battery Power Off Circuit
The hybrid battery power-off control circuit reports a generic fault. Safe disconnection of the HV system cannot be commanded reliably.
- 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.
- Power-off wiring faultCommon
- Main contactor faultPossible
- Pack cell imbalance approaching service thresholdLess likely
Parts involved
- Hybrid Battery Power Off Circuit
- Main Contactors
- Bms
P0A27 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.