P0504

DTC P0504 Brake Switch "A" / "B" Correlation

DESCRIPTION

DTC Detection Condition:

The stop light switch is a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and sets the DTC.






HINT: The normal conditions are as shown in the table given. The signals can be read using the intelligent tester.

Wiring Diagram:

Step 1-2:

Step 3-4:

Step 4(Continued):

INSPECTION PROCEDURE

HINT: Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.