What P0AA6 means
The high-voltage system floats free of the chassis, and an isolation monitor measures the resistance from each HV rail to body ground.
How the engine computer detects it
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.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- 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
Common causes
- Coolant or moisture inside the battery pack, inverter or drive motor Most likely
- Chafed or crushed orange HV cable shorting to the body Possible
- Insulation breakdown in the electric A/C compressor or a motor winding Possible
- Electrolyte leakage or contamination inside the battery sections Less likely
How to diagnose P0AA6
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: hv battery, hv cabling, inverter, charger.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Vehicles that report P0AA6 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Toyota Prius | 2007–2008 | 3 | 150k | |
| Nissan Leaf | 2017–2018 | 3 | — |
Counts of owner complaints to the NHTSA that mention P0AA6 (14 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- A
- Hybrid and electric propulsion
- A6
- Specific fault
Questions drivers ask
Can I drive with code P0AA6?
Have it checked before you drive further. An isolation fault means the high-voltage system may be leaking voltage to the car's body. Many hybrids and EVs limit or shut down the drive system. Never touch orange high-voltage cables, and leave the repair to a shop trained on hybrids.
Often reported together
Codes that owners mention in the same NHTSA complaints as P0AA6. They can point to a shared cause, so it's worth checking them together.
- P31E7Manufacturer-specific code3 complaints
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.