What does code P0504 mean?

Q: What does code P0504 mean?

Brake Switch 'A'/'B' Correlation. P0504 means the powertrain control module (PCM) has detected a disagreement between the two electrical signals produced by the brake pedal switch assembly, which typically contains a normally closed and a normally open contact. The PCM compares these two inputs to confirm the brake pedal position, and when the signals do not correlate for a calibrated period, it stores this code and may disable cruise control or affect shift logic.

DTC codes / P05xx · Vehicle speed, idle control and auxiliary inputs / P0504

P0504Brake Switch 'A'/'B' Correlation

P0504 means the powertrain control module (PCM) has detected a disagreement between the two electrical signals produced by the brake pedal switch assembly, which typically contains a normally closed and a normally open contact. The PCM compares these two inputs to confirm the brake pedal position, and when the signals do not correlate for a calibrated period, it stores this code and may disable cruise control or affect shift logic.

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.