P0AA6 on Chevrolet: How to Diagnose & Fix
Hybrid Battery Voltage System Isolation Fault
1 Chevrolet model · 1 documented issue
P0AA6 on Chevrolet by model: symptoms, diagnosis and fix
First-generation Volts (2011-2015) can experience battery coolant heater failure. The heating coil is located inside the battery pack and can develop isolation faults, causing the vehicle to run on gasoline only when the battery is below 50 degrees F. The poor design placement requires opening the battery pack to test and replace the heater coil. A failing heater coil measures below the required 80 ohms isolation resistance. This significantly reduces EV range in cold weather and can trigger fault codes.
Common Symptoms
- Vehicle runs on gasoline only in cold weather (below 50F)
- Battery will not charge or hold charge in cold temperatures
- Reduced EV range in winter months
- Engine runs constantly even with full battery charge
- Battery coolant temperature warning messages
How to Fix
Have the dealer measure the heater coil resistance (should be 80 ohms). Replacement requires removing and opening the battery pack, which is a major service operation ($1,500-$2,500). Under the Voltec warranty (8yr/100k mi), this is covered at no cost. For out-of-warranty vehicles, some EV specialty shops can perform the repair for less than dealer pricing.
Sources for this issue (1)
P0AA6 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0AA6 mean on a Chevrolet?
P0AA6 stands for "Hybrid Battery Voltage System Isolation Fault." P0AA6 is a hybrid/EV code meaning the battery management system detected an isolation (insulation) fault between the high-voltage battery system and the vehicle's chassis ground. For safety, the high-voltage system is normally electrically isolated from the metal body; this code sets when the measured insulation resistance drops too low, suggesting current could leak to the chassis. This is treated as a serious safety concern and often disables hybrid/EV operation or limits propulsion. The vehicle should be inspected by a qualified hybrid technician, as high-voltage components can pose a shock hazard. On Chevrolet it is documented across 1 model: Volt.
What are the most common causes of P0AA6?
The most common causes of P0AA6 are: Moisture or coolant intrusion inside the high-voltage battery pack, Damaged or chafed insulation on high-voltage cables, Corrosion or water in high-voltage connectors, Failed or leaking battery cell/module, Faulty inverter, converter, or A/C compressor (high-voltage components), Damaged high-voltage wiring rubbing against the chassis, Failed battery isolation/monitoring sensor. The specific cause varies by vehicle.
How much does it cost to fix P0AA6 on a Chevrolet?
Repair costs vary widely with the root cause and Chevrolet model; each issue on this page carries its own estimate where one is published.
Looking for P0AA6 on a different make?
View P0AA6 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.