Powertrain, generic · Hybrid propulsion

P0AF3 Drive Motor Inverter Temperature Sensor B Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

P0AF3 is the plausibility test for inverter temperature sensor B, the phase U sensor of GM's motor B inverter. In the 2016 to 2019 tables the sensor is compared after a cold soak with a calculated average vehicle temperature; a difference above 20 °C sets the code, Type B, two trips. The 2011 Volt compares it with the other power electronics sensors at 20 °C, Type A, and the 2011 and 2013 two-mode trucks after 360 minutes off at 15 °C, Type B. GM bulletin PIC6303A lists P0AF3 with P0AEE and the other inverter thermistor codes on 2016-18 Volt, Malibu, LaCrosse and Regal with the 5ET50 drive: alone they cause no noticeable effect, and the inverter is replaced only if P0AC4 set at the same time.

Likely causes

Inverter temperature sensor B drifting out of tolerance

Failing power inverter module

Uneven inverter coolant flow after soak

Symptoms

Malfunction indicator lamp after two trips
Often no noticeable drivability change
Further inverter temperature codes may be stored

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€100–4,000

Time0.5–6 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

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.