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.
PCM sets DTC P0504 if the PCM detects signal of the brake warning lamp and brake switch do 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
MIL On Condition
-
Test Condition
Brake Test Switch
Brake Light Switch
Step on brake pedal
Battery Voltage
Release brake pedal
Approx. 0V