What does code P28AF mean?

Q: What does code P28AF mean?

Cylinder 8 Ion Current Sense Circuit High. P28AF means the engine control module (ECM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 8, which is used to measure combustion quality. The ECM expects a specific voltage range from the ion sense circuit during each combustion event, and a high reading indicates a short to voltage, an open circuit, or a faulty sensor.

DTC codes / P28xx · Transmission / P28AF

P28AFCylinder 8 Ion Current Sense Circuit High

P28AF means the engine control module (ECM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 8, which is used to measure combustion quality. The ECM expects a specific voltage range from the ion sense circuit during each combustion event, and a high reading indicates a short to voltage, an open circuit, or a faulty sensor.

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.