Brake switch is connected to brake pedal and transmits brake operating state to ECM.
When the output signal of APS is higher than what driver intended during driving (e.g. short to high voltage line in APS circuit, false signal ), driver depresses brake pedal.
Like this, if driver′s decelerating intension is transmitted to ECM (break pedal depressed)when APS output voltage is high, ECM recognizes APS trouble and Limp Home mode is activated.
At Limp Home mode, engine speed is fixed at 1200RPM and engine power generation is limitted.
Even at Limp home mode, if correct APS signal is detected, Limp Home mode is deactivated.
Brake switch, which monitors proper operation of APS, is devided 1 and 2 for the fidelity of brake switch.
When brake switch operates correctly, switch 1 is OFF and switch 2 is ON when releasing brake pedal, while switch 1 is ON and switch 2 is OFF when depressing brake pedal. thus when the signal from a switch is different from the other′s, brake switch is in good condition. When the signal from a switch is same as the other′s, brake switch is fault.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Signal monitoring | ● Brake switch component ● Abnormal brake pedal height ● Brake switch circuit | ||
Enable Conditions | ● IG KEY "ON" | |||
Threshold Value | ● Wiring open | |||
Diagnostic Time | ● 100 sec. | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | NO | |||
Fuel Limit | NO | |||
Check Lamp | NO | |||
Condition | Brake Pedal Released | Brake Pedal Depressed | ||
Switch Activated | Switch 1 | Switch 2 | Switch 1 | Switch 2 |
OFF | ON | ON | OFF | |
