P2E72
Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Low
The cell thickness sensor of HV battery pack B reports voltage below the expected window. 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.
- 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.
- Signal wire shorted to groundCommon
- Internal sensor shortPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Hybrid Battery Pack B
- Hybrid Battery Pack B Thickness Sensor
- Bms
P2E72 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.