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.
Checking output signals from both Stop lamp switch when all of them are On or OFF simultaneously, if abnormal signal is detected for more than 60 sec., an error is recognized. And if this condition lasts for certain period, ECM sets P0504.
Item
Detecting Condition
Possible Cause
DTC Strategy
Plausibility check
Poor connection
Open or short in Stop lamp switch
Faulty Stop lamp switch
Enable Conditions
IG On
Threshold Value
Time brake light switch/brake test switch do not correlate longer than > 1 sec
Diagnostic Time
60 sec
MIL ON Condition
NO MIL
During taking off the brake
During stepping on the brake
Stop Lamp
0V
Battery voltage
Stop Lamp Switch