P0504
DTC P0504
CIRCUIT DESCRIPTION
The signal of the stop lamp switch is used to determine whether the brake system is abnormal or not. The stop lamp switch has a duplex system (signals STP and ST1) to detect an abnormality. When the signals of depressing and releasing the brake pedal are detected simultaneously, the engine control module (ECM) interprets this as a malfunction of the stop lamp switch.
CONDITIONS FOR RUNNING THE DTC
The ignition is ON.
CONDITIONS FOR SETTING THE DTC
The brake pedal is released, if the status of the stop lamp switch input signal to the ECM does not match for at least 0.5 seconds or more the DTC will set.
ACTION TAKEN WHEN THE DTC SETS
When DTC P0504 is set the following will occur:
- The cruise control is disabled.
- The ECM will function as if the brake pedal is not pressed.
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
CONDITIONS FOR CLEARING THE DTC
- The DTC will clear when the status of the stop lamp switch input signals to the ECM match for at least 0.5 seconds continuously for both the pressed position and the released position.
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- Clear the DTC with a scan tool.
DIAGNOSTIC AIDS
- Inspect for proper adjustment of the stop lamp switch. Refer to Stop Lamp Switch Adjustment.
- Check for intermittents and poor connections.
TEST
