P0E21
Hybrid/EV Battery Pack Coolant Control Valve B Control Circuit Driver Current/Temperature Too High
The output driver for hybrid/ev battery pack coolant control valve b reports current or junction temperature above its protection threshold.
- 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.
- Actuator stalled - high stall currentCommon
- Control wire shorted to groundPossible
- Pack cell imbalance approaching service thresholdLess likely
Parts involved
- Hv Battery Pack Coolant Valve B
- Bms
P0E21 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.