P0AA6Hybrid/EV Battery Voltage System Isolation Fault
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- The high-voltage system floats free of the chassis, and an isolation monitor measures the resistance from each HV rail to body ground. P0AA6 sets when that resistance falls below a calibrated limit. GM tables measure with the contactors open and fail below 75,000 ohms (2016) or 213,000 ohms (2019), Type A, one trip; Volt bulletins expect over 275 kOhm after repair, while FMVSS 305 sets 100 ohms per volt DC as the post-crash floor. Documented causes: Volt battery coolant leaks, a chafed HV harness on Ford Aviator/Explorer hybrids, a traction motor coolant leak on the 2017 Ioniq Hybrid; Toyota adds INF codes naming the area. P0AA7 to P0AAB flag the measuring circuit itself. Expect warnings, no charging or a stop-safely message.
- What you may notice
- Check engine and hybrid or EV system warning lights
- Vehicle will not charge or will not enter ready mode after restart
- Stop safely now message or reduced power
- Likely causes
- LikelyCoolant or moisture inside the battery pack, inverter or drive motor
- PossibleChafed or crushed orange HV cable shorting to the body
- PossibleInsulation breakdown in the electric A/C compressor or a motor winding
- RareElectrolyte leakage or contamination inside the battery sections
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €200 – €8,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.