What does code P257C mean?

Q: What does code P257C mean?

Vacuum Reservoir Control Circuit High. P257C indicates the powertrain control module (PCM) has detected an abnormally high voltage on the vacuum reservoir control circuit, which typically points to an open circuit, a short to voltage, or a failed control solenoid. The PCM commands the vacuum reservoir control solenoid to manage engine vacuum storage, and when the feedback signal exceeds the expected range, it sets this code and may disable the related vacuum assist features.

DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P257C

P257CVacuum Reservoir Control Circuit High

P257C indicates the powertrain control module (PCM) has detected an abnormally high voltage on the vacuum reservoir control circuit, which typically points to an open circuit, a short to voltage, or a failed control solenoid. The PCM commands the vacuum reservoir control solenoid to manage engine vacuum storage, and when the feedback signal exceeds the expected range, it sets this code and may disable the related vacuum assist features.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

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