P2C88
Hybrid/EV Battery Voltage System Isolation Warning
The hybrid control module detects a system-wide isolation warning across multiple HV components. General insulation degradation.
- 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.
- Multiple low-grade insulation faultsCommon
- High ambient humidity affecting multiple componentsPossible
- Pack cell imbalance approaching service thresholdLess likely
Parts involved
- Hv Battery
- Hv Wiring
- Isolation Monitor
P2C88 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.