What does code P28A3 mean?

Q: What does code P28A3 mean?

Cylinder 5 Ion Current Sense Circuit High. P28A3 means the engine control module (ECM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 5, which is the feedback line used to measure combustion ionization. The ECM expects a specific voltage range during each combustion event, and a reading above the calibrated threshold indicates a short to voltage, an open return path, or a faulty sensor interface.

DTC codes / P28xx · Transmission / P28A3

P28A3Cylinder 5 Ion Current Sense Circuit High

P28A3 means the engine control module (ECM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 5, which is the feedback line used to measure combustion ionization. The ECM expects a specific voltage range during each combustion event, and a reading above the calibrated threshold indicates a short to voltage, an open return path, or a faulty sensor interface.

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.