What does code P28B3 mean?

Q: What does code P28B3 mean?

Cylinder 9 Ion Current Sense Circuit High. P28B3 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 9, which is used to measure combustion quality. The circuit is reporting a signal above the expected range, so the PCM cannot reliably assess ignition and knock events for that cylinder.

DTC codes / P28xx · Transmission / P28B3

P28B3Cylinder 9 Ion Current Sense Circuit High

P28B3 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the ion current sense circuit for cylinder 9, which is used to measure combustion quality. The circuit is reporting a signal above the expected range, so the PCM cannot reliably assess ignition and knock events for that cylinder.

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.