What does code P28C4 mean?

Q: What does code P28C4 mean?

Clutch A Phase U-V-W Circuit Low. P28C4 indicates that the transmission control module (TCM) or hybrid control module has detected a low-voltage condition on the phase U, V, or W circuit for clutch A, which is typically an electrically actuated clutch in a dual-clutch or hybrid transmission. The computer monitors the current or voltage on these three phase circuits and sets the code when the signal falls below the expected threshold, indicating an open circuit, short to ground, or faulty clutch actuator.

DTC codes / P28xx · Transmission / P28C4

P28C4Clutch A Phase U-V-W Circuit Low

P28C4 indicates that the transmission control module (TCM) or hybrid control module has detected a low-voltage condition on the phase U, V, or W circuit for clutch A, which is typically an electrically actuated clutch in a dual-clutch or hybrid transmission. The computer monitors the current or voltage on these three phase circuits and sets the code when the signal falls below the expected threshold, indicating an open circuit, short to ground, or faulty clutch actuator.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.