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 brake switch when all of them are On or OFF simultaneously, if abnormal signal is detected for more than 0.5 sec., an error is recognized. And if this condition lasts for certain period, PCM sets P0504. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Comparing 2 brake signals during driving | ● Poor connection ● Open or short in brake switch ● Faulty Brake switch |
Enable Conditions | Case 1 | ● Engine works ● Vehicle Speed Sensor is abnormal. |
Case 2 | ● Engine works ● Vehicle Speed Sensor is normal and Vehicle Speed is over 20kph during 1sec or more. | |
Threshold value | ● The one brake signal’s change duration when another signal has been changed ＞ 0.5 sec | |
Diagnosis Time | ● Continuous | |
MIL On Condition | ● 2 driving cycles |
Item | During taking off the brake | During stepping on the brake |
Brake Lamp Switch | 0V | Battery voltage |
Brake Switch | Battery voltage | 0V |
