P0AF8
Hybrid/EV Battery System Voltage
The hybrid control module detects a generic fault on the HV battery system voltage. 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.
- Cell imbalanceCommon
- Sense circuit faultPossible
- Ground point with elevated resistanceLess likely
Parts involved
- Hv Battery
- Bms
P0AF8 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.