OBD-II code · Powertrain (generic, extended)
P2C85 Hybrid/EV Battery Voltage External Isolation Fault
The hybrid control module detects an isolation fault between the high-voltage battery and the vehicle chassis. Indicates degraded HV insulation.
Is it safe to drive with P2C85?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyHV cable insulation chafed against chassis
- PossibleMoisture in HV connector
- Less likelyPack cell imbalance approaching service threshold
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 3–16 h
- Emissions test
- Usually unaffected
- Parts involved
- Hv Battery, Hv Wiring, Isolation Monitor
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.