P0A31Drive Motor B Temperature Sensor Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- 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
- Likely causes
- LikelyMotor B thermistor reading drifted out of tolerance
- PossibleCorroded terminals adding resistance in the sensor circuit
- RareComparison sensor (inverter, coolant or fluid temperature) is wrong
- RareUneven cooling of the drive unit, e.g. low fluid level
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.