Hybrid/EV Battery Voltage Internal Isolation Warning
The hybrid control module detects an internal isolation warning inside the high-voltage battery pack. Pre-failure indicator for cell or busbar insulation.
Affected components
- Hv battery
- Hv wiring
- Isolation monitor
Common causes
- High likelihood: Cell insulation aged
- Medium likelihood: Busbar approaching housing
- 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.