What it means
The current sensor for drive motor A phase W reports a circuit fault. Phase current measurement is unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Drive motor A’s inverter controls current in the motor’s W phase, and a current sensor reports that phase’s current to the control module. This code sets when the phase W sensor circuit has a fault, making the module’s measurement unreliable and potentially limiting motor output.
Common causes
Most likely first.
- Current sensor failed
- Wiring fault
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Record freeze-frame data and review live drive motor A phase W current readings alongside related inverter codes to identify the conditions when the fault appears.
- With the high-voltage system made safe according to the manufacturer's procedure, inspect the phase W sensor and connector for damage, loose pins, corrosion, or harness chafing.
- Use the manufacturer's wiring diagram to check the phase W sensor signal, supply, and ground for open circuits, shorts, or poor connections.
- Compare phase W readings with drive motor A phases U and V under comparable conditions to see whether the fault is isolated to W.
- If the wiring checks pass, test the drive motor A phase W current sensor using the manufacturer's diagnostic procedure and replace it if faulty.
Common fixes
- Secure or clean a loose or corroded phase W sensor connector.
- Repair damaged, open, or shorted wiring in the phase W sensor circuit.
- Restore a poor sensor supply or ground connection.
- Replace the drive motor A phase W current sensor if the circuit is sound and the sensor fails testing.
Can I keep driving?
If the vehicle has reduced torque, limp mode, or an EV/hybrid warning, avoid high-speed trips and situations where sudden loss of drive would be hazardous. A severe fault can lead to a shutdown.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.