ASCD Brake Switch

ASCD BRAKE SWITCH





Description
When the brake pedal is depressed, ASCD brake switch is turned OFF and stop lamp switch is turned ON.
ECM detects the state of the brake pedal by those two types of input (ON/OFF signal). System Diagram for the ASCD function.




Component Function Check
Regarding Wiring Diagram information, [1][2]Electrical Diagrams.
1.CHECK ASCD BRAKE SWITCH FUNCTION
With CONSULT-III
1. Turn ignition switch ON.
2. Select "BRAKE SW1" in "DATA MONITOR" mode with CONSULT-III.
3. Check "BRAKE SW1" indication under the following conditions.





Without CONSULT-III
1. Turn ignition switch ON.





2. Check the voltage between ECM harness connectors.





Is the inspection result normal?
YES - INSPECTION END
NO - Go to SEE Diagnosis Procedure.




Diagnosis Procedure
Regarding Wiring Diagram information, [1][2]Electrical Diagrams.
1.CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Turn ignition switch ON.





4. Check the voltage between ASCD brake switch harness connector and ground.





Is the inspection result normal?
YES - GO TO 3.
NO - GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
- Fuse block (J/B) connector E6
- Junction block connectors E44, E46
- 10 A fuse (No. 3)
- Harness for open or short between ASCD brake switch and fuse
- Repair open circuit, short to ground or short to power in harness or connectors.
3.CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between ASCD brake switch harness connector and ECM harness connector.





4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES - GO TO 5.
NO - GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
- Junction block connectors E45, E46
- Harness for open or short between ASCD brake switch and ECM
- Repair open circuit, short to ground or short to power in harness or connectors.
5.CHECK ASCD BRAKE SWITCH
SEE Component Inspection (ASCD Brake Switch).
Is the inspection result normal?
YES - GO TO 6.
NO - Replace ASCD brake switch. Removal And Installation.
6.CHECK INTERMITTENT INCIDENT
Intermittent Incident.
- INSPECTION END




Component Inspection (ASCD Brake Switch)
1.CHECK ASCD BRAKE SWITCH-I
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.





3. Check the continuity between ASCD brake switch terminals under the following conditions.





Is the inspection result normal?
YES - INSPECTION END
NO - GO TO 2.
2.CHECK ASCD BRAKE SWITCH-II
1. Adjust ASCD brake switch installation. Inspection and Adjustment.





2. Check the continuity between ASCD brake switch terminals under the following conditions.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace ASCD brake switch. Exploded View Removal And Installation.