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.
Affected components
- Hv battery
- Hv wiring
- Isolation monitor
Common causes
- High likelihood: HV cable insulation chafed against chassis
- Medium likelihood: Moisture in HV connector
- Low likelihood: Pack cell imbalance approaching service threshold
Possible symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
Diagnostic notes
- The malfunction indicator lamp may illuminate
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.