P0A90Drive Motor A Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0A90 reports that electric drive motor A does not behave as commanded. In GM's eAssist mild hybrid the motor/generator is belt-driven from the crankshaft, so GM uses P0A90 to detect a slipping or broken belt: the motor speed is compared with the engine speed. In 2013 a difference above 1000 rpm for 1.5 s, or repeated smaller slips above 500 rpm on two key cycles, set it; the 2016 tables use more than 1500 rpm for about 5.6 s or repeated 1000 rpm slip events. GM rates it Type A, MIL on the first trip. In full hybrids the generic definition applies to speed or torque deviations of the traction motor. P0A91 is the equivalent for motor B, P0A92 for the generator.
- What you may notice
- MIL and hybrid system warning
- Belt squeal or auto-stop/start not working
- Reduced electric assist or limp mode
- Likely causes
- LikelySlipping, worn or broken drive belt on belt-driven motor/generators
- PossibleFaulty belt tensioner or contamination on the belt
- PossibleMotor, position sensor or inverter fault in full hybrids
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.