OBD-II code · Powertrain (generic)

P0AA3 Hybrid/EV Battery Negative Contactor Circuit

The HV battery negative contactor circuit reports a generic fault. HV system grounding cannot be commanded reliably.

Is it safe to drive with P0AA3?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelyContactor failed
  • PossibleWiring fault
  • Less likelyPack cell imbalance approaching service threshold

Symptoms

  • EV/hybrid system warning light on
  • Reduced power output or limp mode
  • Charging may fail or be slowed
  • Reduced electric range

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
2–8 h
Emissions test
Usually unaffected
Parts involved
Hv Battery Negative Contactor, Bms

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.