OBD-II code · Powertrain (generic)

P0AAB Hybrid/EV Battery Voltage Isolation Sensor Circuit Intermittent/Erratic

The ECM detects a circuit intermittent/erratic fault on the hybrid/ev battery voltage isolation sensor circuit. Reading cannot be used reliably for control.

Is it safe to drive with P0AAB?

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

Common causes

  • Most likelySensor connector not seated
  • PossibleNoisy ground reference
  • Less likelyConnector with intermittent contact under vibration

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
2–7 h
Emissions test
Usually unaffected
Parts involved
Hv Battery Voltage Isolation Sensor, Wiring Harness, Bms

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