What it means
The current sensor for drive motor A phase U 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
The inverter controls motor torque by switching current through the motor’s three phases. A current sensor measures phase U of drive motor A so the control module can regulate that current. This code indicates a circuit fault in that phase U sensor circuit, making the measurement unreliable.
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 scan for other drive motor A or inverter codes to see whether the fault is isolated to phase U.
- Check available live data for drive motor A phase U current and compare its behavior with phases V and W under comparable conditions.
- With the vehicle powered down under the manufacturer’s high-voltage safety procedure, visually inspect accessible phase U sensor wiring and connectors for damage, loose fit, or corrosion.
- Have a qualified technician test the phase U current sensor circuit and its connections using the manufacturer’s wiring information and specification.
- If the circuit wiring and connections pass, test the phase U current sensor itself and compare its response with the manufacturer’s specification.
Common fixes
- Repair loose, damaged, or corroded phase U sensor wiring and connector terminals.
- Restore secure electrical connections at the phase U current sensor.
- Replace the phase U current sensor if testing confirms it has failed.
- Clear the code and verify phase U current data during the manufacturer’s prescribed check.
Can I keep driving?
Limit driving because unreliable phase U current feedback can cause reduced torque, limp mode, or a vehicle shutdown. Avoid high-speed or high-load trips, and stop safely if power becomes unpredictable.
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.