OBD-II · Engine and powertrain (P)
P0AA6
High-voltage isolation fault
What it means
The system has detected electrical leakage from the high-voltage system to the car body, which is a shock risk.
Symptoms
- Hybrid/EV warning light
- Car may not go into READY or will not charge
- Sometimes only after rain or washing
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | electric air-conditioning compressor insulation breakdown (common on hybrids) |
| 02 | water ingress into a high-voltage connector or component |
| 03 | high-voltage cabin heater (PTC) fault on EVs |
| 04 | damaged orange high-voltage cable |
| 05 | internal leakage in the battery pack, inverter or motor |
What to check, step by step
- 01Do not touch orange high-voltage cables or components
- 02Have a high-voltage qualified technician measure isolation resistance component by component
- 03Check the electric A/C compressor and high-voltage heater first, as they are frequent causes
- 04Inspect high-voltage connectors and cables for water and damage