The Stop lamp switch is used to judge whether the acceleration system is abnormal or not. The stop lamp switch has a duplex system(signals brake test or brake light) to memorize the abnormality when the signals of depressing and releasing the brake pedal are detected simultaneously.
ECM sets DTC P0504 if the ECM detects signal of the brake warning lamp and brake switch are not correlate within the predetermined time.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Plausibility check between Brake Light Switch(BLS) and Brake Test Switch(BTS)
? Open or short circuit in harness
? Poor connection or damaged harness
? Faulty brake warning lamp or brake test switch
Enable Conditions
? Engine running
Threshold Value
? Time between brake light switch and brake test switch do not correlate longer than > 10 sec
Diagnostic Time
? 12 times brake pedal activation
Test Condition
Brake warning switch
Brake test switch
Brake pedal depressed
Battery voltage
Approx. 0V
Brake pedal released