What does code P25C9 mean?

Q: What does code P25C9 mean?

Brake System Control Module B Requested MIL Illumination. P25C9 means the brake system control module (the computer that manages anti-lock braking, stability control, and often the electric parking brake) has asked the engine control module to turn on the malfunction indicator lamp (MIL, the check engine light). The engine computer stores this code because it received a valid request for illumination over the vehicle network, not because it found an engine fault itself.

DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P25C9

P25C9Brake System Control Module B Requested MIL Illumination

P25C9 means the brake system control module (the computer that manages anti-lock braking, stability control, and often the electric parking brake) has asked the engine control module to turn on the malfunction indicator lamp (MIL, the check engine light). The engine computer stores this code because it received a valid request for illumination over the vehicle network, not because it found an engine fault itself.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

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.