What it means
The output stage for the clutch A BLDC motor reports a low phase voltage on at least one of the U/V/W phases. Short to ground or interrupted half-bridge.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The clutch A BLDC motor is driven by three electrical phases, labelled U, V, and W, to operate the clutch actuator. This code sets when the output stage detects that at least one phase voltage is too low, which can indicate a phase wire shorted to ground, a failed low-side driver, or a high-resistance connection.
Common causes
Most likely first.
- Phase wire shorted to ground
- Low-side switch open in driver
- Connector pins corroded - high contact resistance
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Read transmission freeze-frame data and live clutch A commands, phase readings, and gear status to understand when the low-phase fault occurs.
- Inspect the clutch A U, V, and W wiring and connectors for damage, corrosion, loose terminals, or contact with ground.
- Check the phase wiring for shorts to ground using the manufacturer's wiring diagram and isolation procedure.
- Have phase voltages and output-stage operation checked under the manufacturer's specified conditions, without applying power to the motor outside the prescribed test.
- If the wiring and connections pass, test the clutch A driver and motor according to the manufacturer's procedure.
Common fixes
- Clean and secure corroded or loose clutch A phase connector terminals.
- Repair a U, V, or W phase wire shorted to ground.
- Repair or replace a confirmed faulty low-side driver in the output stage.
- Replace a confirmed faulty clutch A motor or driver assembly.
Can I keep driving?
Avoid driving if shifts are harsh, delayed, slipping, or the vehicle is locked in one gear; arrange recovery if gear control is unreliable. Continued driving can worsen clutch or transmission damage.
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.