P0A40 Possible Causes
- Faulty drive motor generator
- Drive motor harness is open or shorted
- Poor electrical connection in drive motor generator circuit
What Does It Mean?
How to Fix Code P0A40
Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
P0A40 Possible Symptoms
Malfunction Indicator Light illuminated (or Service Engine Soon warning light)
P0A40 Meaning
The drive motor position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed, and direction of the drive motor generator rotor based on signals from the resolver-type position sensor. The position sensor contains one drive coil, two driven coils, and an irregularly shaped metal rotor. The metal rotor is mechanically attached to the drive motor-generator shaft. When the vehicle is turned on, the motor control module delivers a 7V AC, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregularly shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metal rotor causes the magnetically induced return signals from the driven coils to vary in size and shape. A comparison of the two signals from the driven coils allows the motor control module to determine the exact position, speed, and direction of the drive motor-generator rotor. The position sensor is a non-repairable part of the drive motor.