What does code P0398 mean?

Q: What does code P0398 mean?

Cylinder 1 Pressure Sensor Circuit High. P0398 indicates that the powertrain control module has detected an abnormally high voltage signal from the cylinder 1 pressure sensor circuit, which is used on some engines to monitor combustion pressure for feedback control. The computer expects the sensor signal to stay within a calibrated voltage range, and a sustained high reading tells it the circuit is open, shorted to voltage, or the sensor itself has failed.

DTC codes / P03xx · Ignition system and misfire / P0398

P0398Cylinder 1 Pressure Sensor Circuit High

P0398 indicates that the powertrain control module has detected an abnormally high voltage signal from the cylinder 1 pressure sensor circuit, which is used on some engines to monitor combustion pressure for feedback control. The computer expects the sensor signal to stay within a calibrated voltage range, and a sustained high reading tells it the circuit is open, shorted to voltage, or the sensor itself has failed.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.