P0E12
Hybrid/EV Battery Pack Coolant Heater A Control Circuit/Open
The HV battery pack coolant heater A reports a control circuit/open condition. Battery preheating may be impaired in cold weather.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
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.
- Open in heater control wireCommon
- Open heater elementPossible
- Pin pushed back out of connector bodyLess likely
Parts involved
- Hv Battery Pack Coolant Heater A
- Wiring Harness
- Bms
P0E12 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.