P0AA0Hybrid/EV Battery Positive Contactor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The positive main contactor is a high-voltage relay that connects the positive pole of the traction battery to the propulsion bus. P0AA0 is the general fault code for this contactor circuit, used when the controller sees a problem it does not split into stuck closed (P0AA1), stuck open (P0AA2) or the control-circuit codes P0AD9 to P0ADC. No manufacturer documents this exact code publicly; GM, Audi, Jeep and Mitsubishi report the specific siblings instead. NHTSA's Mach-E recall query shows the underlying failure modes: overheated contacts that stay open or weld shut. With the positive side unusable the car may refuse ready mode or drop propulsion; work on it requires high-voltage qualification.
- What you may notice
- Vehicle does not enter ready or propulsion-active mode
- Hybrid or EV system warning with check engine light
- Possible loss of propulsion while driving
- Likely causes
- LikelyPositive contactor or battery junction box worn or damaged
- PossibleFault in the contactor coil feed or its connector
- RareWeak 12 V supply so the contactor does not pull in reliably
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.