P2E71: Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit High
Standardized SAE J2012 code · P2Exx codes
What does P2E71 mean?
The cell thickness sensor of HV battery pack B reports voltage above 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.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Common causes
- High Signal wire shorted to B+
- Medium Open sensor
- Low Connector pins corroded - high contact resistance
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2E71 on the same make and model first.
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