What does code P28A1 mean?

Q: What does code P28A1 mean?

Cylinder 5 Ion Current Sense Circuit Range/Performance. P28A1 indicates that the engine control module (ECM) has detected an out-of-range or poor-performance signal from the ion current sense circuit for cylinder 5. This circuit monitors the electrical conductivity of the combustion gases to assess combustion quality, and the ECM sets the code when the signal voltage or current does not match expected values for the current operating conditions.

DTC codes / P28xx · Transmission / P28A1

P28A1Cylinder 5 Ion Current Sense Circuit Range/Performance

P28A1 indicates that the engine control module (ECM) has detected an out-of-range or poor-performance signal from the ion current sense circuit for cylinder 5. This circuit monitors the electrical conductivity of the combustion gases to assess combustion quality, and the ECM sets the code when the signal voltage or current does not match expected values for the current operating conditions.

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.