P2B21
Hybrid/EV Electronics Coolant Temperature Sensor B Range/Performance
The vehicle hybrid control module detects a range/performance fault on the coolant temperature sensor B that monitors the power electronics cooling loop.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor characteristic driftedCommon
- Sensor mounting displacedPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Hybrid Electronics Coolant Temp Sensor B
- Wiring Harness
- Hybrid Control Module
P2B21 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.