Powertrain, generic · Hybrid propulsion

P0AF6 Drive Motor Inverter Temperature Sensor B Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0AF6 targets an inverter temperature sensor B signal that jumps or drops out briefly. Since the heat sink of the motor B inverter is liquid-cooled and warms or cools gradually, abrupt changes in the reading indicate a contact problem or an intermittent fault in the sensing circuit rather than real temperature. No manufacturer documents this exact code publicly; GM's hybrid tables only list P0AF3, P0AF4 and P0AF5 for sensor B. For erratic battery temperature sensors such as P0AEC, GM sums the signal changes over 10-sample windows and fails after 4 of 5 bad windows, a likely model for this check. CARB requires sensor inputs of hybrid systems to be checked for erratic behaviour. Watch live data while gently moving the inverter harness.

Likely causes

Loose or corroded connector at the inverter module
Intermittent fault inside the power inverter module
Electrical interference on the sensor signal

Symptoms

  • Warning lamp that comes and goes
  • Brief reductions of motor B power
  • Jumping inverter temperature in live data

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–4,000
Time1–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

drive motor inverter temp sensor bhybrid control modulewiring harness

Related codes

P0AF2P0AF3P0AF4P0AF5P0AF1

References: law.cornell.edu, gsi.ext.gm.com.