What are the common causes of P0AA0?

A worn or pitted positive contactor. High resistance or corrosion in the positive contactor circuit. An open or short in the positive contactor wiring. A failing battery management system. A battery state of charge out of range.

Check the positive contactor coil for power and ground. Measure resistance across the positive contactor. Inspect the positive contactor wiring for corrosion. Compare the positive and negative contactor readings. Replace the positive contactor if resistance is out of range. Clear the code and retest.

P0AA0

Hybrid/EV Battery Positive Contactor Circuit

System: Powertrain control (P code)
Lamp: Check Engine Light
Category: Powertrain - Hybrid Propulsion

What it means

P0AA0 means Hybrid/EV Battery Positive Contactor Circuit.

Check these first

A worn or pitted positive contactor
High resistance or corrosion in the positive contactor circuit
An open or short in the positive contactor wiring
A failing battery management system
A battery state of charge out of range

What to do next

Check the positive contactor coil for power and ground
Measure resistance across the positive contactor
Inspect the positive contactor wiring for corrosion
Compare the positive and negative contactor readings
Replace the positive contactor if resistance is out of range
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.