P28C4
Clutch A Phase U-V-W Circuit Low
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.
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.
Common causes
- high
Phase wire shorted to ground
One of the most commonly reported causes for this code — check this first.
Typical part cost: $550-3080
- medium
Low-side switch open in driver
A plausible cause — test and verify before replacing parts.
Typical part cost: $550-3080
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P28C4.
Unlock causesFree forever · No credit card
First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
Get the full step-by-step diagnosis
Create a free Wrenchify account to unlock the rest for P28C4.
Unlock diagnosisFree forever · No credit card
Related codes
See related trouble codes
Create a free Wrenchify account to unlock the rest for P28C4.
Unlock related codesFree forever · No credit card
Frequently asked questions
What does P28C4 mean?
P28C4 means "Clutch A Phase U-V-W Circuit Low". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P28C4?
phase wire shorted to ground; low-side switch open in driver; connector pins corroded - high contact resistance — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.
Get the full P28C4 diagnosis for your vehicle
Year, make, model + step-by-step repair help — free plan included.