What it means
The BMS detects an isolation fault in the battery charging system. HV insulation between charging path and chassis is degraded.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery management system monitors electrical isolation between the high-voltage charging path and the vehicle chassis. This code sets when insulation in that charging path is degraded, including from chafed charging-cable insulation or moisture in the charging connector, and the system may restrict charging to reduce risk.
Common causes
Most likely first.
- Charging cable insulation chafed
- Moisture in charging connector
Symptoms
- Hybrid/EV system warning light or charging-system message
- Charging may be limited or unavailable
How to diagnose it
- Note the charging message and freeze-frame data, then check whether the fault occurs during charging or remains present afterward.
- Stop charging and inspect the accessible charging cable and connector exterior for cuts, abrasion, moisture, or visible damage.
- Check the vehicle’s charging inlet for moisture, debris, or damaged seals without touching high-voltage contacts.
- Have the charging-path isolation checked using the manufacturer’s specified procedure and equipment.
- If the cable and inlet appear sound, have the charging circuit and isolation monitoring components checked for an internal fault.
Common fixes
- Dry and clean the charging connector exterior and inlet as permitted by the manufacturer.
- Replace a charging cable with damaged insulation.
- Repair or replace a damaged charging inlet seal or connector assembly.
- Repair the charging-path isolation fault identified by the specified test.
Can I keep driving?
Do not charge the vehicle while the isolation warning is active or the connector or cable is wet or damaged. Charging may be blocked or limited; have the fault assessed promptly, and avoid handling exposed or damaged high-voltage components.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.