P0A4A
Drive Motor B Position Sensor Circuit Overspeed
The drive motor B rotor position sensor reports a circuit overspeed fault. Phase commutation cannot be controlled reliably.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
Common causes
Ordered by how often each turns out to be the cause.
- Rotor position out of expected rangeCommon
- Position signal lost - default to overspeed indicationPossible
Parts involved
- Drive Motor B Position Sensor
- Wiring Harness
- Hybrid Control Module
P0A4A is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.