What does code P28B4 mean?

Q: What does code P28B4 mean?

Cylinder 10 Ion Current Sense Circuit. P28B4 indicates that the engine control module (ECM) has detected an abnormal signal on the ion current sense circuit for cylinder 10, which is used to monitor combustion quality and detect misfires. The ECM expects a specific voltage or current pattern during the ionization phase after each firing event, and the signal is outside the expected range or missing entirely.

DTC codes / P28xx · Transmission / P28B4

P28B4Cylinder 10 Ion Current Sense Circuit

P28B4 indicates that the engine control module (ECM) has detected an abnormal signal on the ion current sense circuit for cylinder 10, which is used to monitor combustion quality and detect misfires. The ECM expects a specific voltage or current pattern during the ionization phase after each firing event, and the signal is outside the expected range or missing entirely.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

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.