What it means
The current sensor for drive motor A phase U reports a circuit high 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 current sensor on drive motor A phase U reports current to the inverter control system, which uses it to regulate motor output. The ECM monitors the sensor circuit and sets this code when the signal is higher than its usable range. A high or invalid signal prevents reliable phase U current control.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
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 phase codes to see whether the high reading is isolated to phase U.
- Compare live phase U current data with phases V and W and check whether phase U is fixed high or implausible for the vehicle’s operating state.
- With the high-voltage system safely disabled, inspect accessible phase U wiring and connectors for an open conductor, a loose terminal, or a signal wire contacting power.
- Have a qualified technician test the phase U sensor circuit for an open or short to power and inspect connector contact using manufacturer wiring information.
- If the circuit checks pass, test the phase U current sensor for an open element according to the manufacturer’s specification.
Common fixes
- Reconnect or repair loose phase U sensor wiring and terminals.
- Repair a signal wire shorted to power or an open in the phase U circuit.
- Replace corroded or poorly contacting connector terminals.
- Replace the phase U current sensor if testing confirms it is open, then verify the live reading.
Can I keep driving?
Limit driving and avoid hard acceleration because the inverter may reduce torque or enter limp mode when phase U current data is invalid. Stop safely if power drops sharply or a shutdown warning appears.
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.