What does code P28B9 mean?

Q: What does code P28B9 mean?

Cylinder 11 Ion Current Sense Circuit Range/Performance. P28B9 indicates that the engine control module has detected an out-of-range or performance fault in the ion current sense circuit for cylinder 11, which is used to monitor combustion quality through ionization at the spark plug gap. The circuit's signal voltage or timing does not match expected values during engine operation, prompting the module to set this code.

DTC codes / P28xx · Transmission / P28B9

P28B9Cylinder 11 Ion Current Sense Circuit Range/Performance

P28B9 indicates that the engine control module has detected an out-of-range or performance fault in the ion current sense circuit for cylinder 11, which is used to monitor combustion quality through ionization at the spark plug gap. The circuit's signal voltage or timing does not match expected values during engine operation, prompting the module to set this code.

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.