Brake SW/Stop/L SW

BRAKE SW/STOP/L SW

System Description
ASCD operation is canceled by pressing the brake pedal or by shifting A/T selector lever to P or N position. Power is supplied to control unit through ASCD brake switch and park/neutral position relay. If this power is cut at any point in the circuit ASCD operation is canceled.
When brake pedal is pressed, power is supplied from stop lamp switch to ASCD control unit. This will also cancel ASCD operation.

Possible Cause
- ASCD brake switch
- Stop lamp switch
- Park/neutral position relay
- Park/neutral position switch
- Circuit open or short

Diagnostic Repair Procedure (for confirmed incidents)
1. Check ASCD brake switch input signal: Using CONSULT-II DATA MONITOR, confirm that BRAKE SW indicates OFF when brake pedal is pressed or A/T selector lever is in N or P. Confirm that ON is indicated when brake pedal is released and A/T selector lever is not in N or P
a. Check power supply to ASCD brake switch with ignition switch ON: Spec = Battery voltage.
b. Check ASCD brake switch: Continuity through it in the released position and no continuity through it in the depressed position.
c. Check power supply to park/neutral position switch: Spec = Battery voltage.
d. Check park/neutral position switch: Continuity through it in either P or N position, and no continuity through it in any other position.
e. Check park/neutral position switch circuit: Continuity/No shorts to ground.
f. Check park/neutral position relay: Use normal methods for relay testing.
g. Check ASCD brake switch circuit: Continuity/No shorts to ground.

2. Check stop lamp switch input signal: Use CONSULT-II DATA MONITOR to confirm that STOP LAMP SW indicates OFF when brake pedal is released and ON when brake pedal is depressed.
a. Check power supply to stop lamp switch.
b. Check stop lamp switch: Continuity through it in the depressed position and no continuity through it in the released position.
c. Check between stop lamp switch and ASCD control unit: Continuity/No shorts to ground.