Powertrain, generic · Hybrid propulsion

P0A31 Drive Motor B Temperature Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0A31 checks whether the motor B temperature reading makes sense, typically after a long rest when all parts should be close to the same temperature. GM compares it with other temperatures: the 2011 tables flag a gap above 20 °C to the average of power-electronics coolant and transmission fluid after 6 h without propulsion (Type A); the 2013 two-mode trucks allow 28 °C against the inverter module after 360 min key-off (Type B, two trips). Mitsubishi (2023 Outlander PHEV rear motor) compares two coil sensors after 5,400 s soak and sets it at 13 °C difference. P0A32 and P0A33 cover hard circuit faults; P0A35 is only judged while this test passes. Expect a hybrid warning and limited electric drive.

Likely causes

Motor B thermistor reading drifted out of tolerance
Corroded terminals adding resistance in the sensor circuit
Comparison sensor (inverter, coolant or fluid temperature) is wrong
Uneven cooling of the drive unit, e.g. low fluid level

Symptoms

  • Hybrid warning light after a cold start
  • Motor B temperature differs clearly from other temperatures after a long rest
  • Electric drive limited as a precaution

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,000
Time1–6 h

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

Parts involved

drive motor b temp sensorwiring harnesshybrid control module

Related codes

P0A30P0A32P0A33P0A35P0A2B

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