What does code P28C1 mean?

Q: What does code P28C1 mean?

Ion Sense Module Supply Voltage Low. P28C1 indicates that the ion sense module has detected a supply voltage that is lower than the manufacturer's expected range, which can prevent the module from accurately measuring ionization current in the combustion chamber. The engine control module (ECM) sets this code when the voltage feed to the ion sense module falls below a calibrated threshold for a specified time, often due to a wiring fault, poor connection, or a failing module.

DTC codes / P28xx · Transmission / P28C1

P28C1Ion Sense Module Supply Voltage Low

P28C1 indicates that the ion sense module has detected a supply voltage that is lower than the manufacturer's expected range, which can prevent the module from accurately measuring ionization current in the combustion chamber. The engine control module (ECM) sets this code when the voltage feed to the ion sense module falls below a calibrated threshold for a specified time, often due to a wiring fault, poor connection, or a failing module.

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.