Stop Light Switch Circuit Malfunction

CRUISE CONTROL: DYNAMIC RADAR CRUISE CONTROL SYSTEM: P0571: Stop Light Switch Circuit Malfunction

DTC P0571 - Stop Light Switch Circuit Malfunction

DESCRIPTION

The ECM receives the brake demand signal from the distance control ECU and transmits it to the skid control ECU.
The skid control ECU receives a signal from the ECM and operates the brake actuator.
The skid control ECU operates the brake actuator and at the same time illuminates the stop light by operating the BRK-LP relay.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK STOP LIGHT OPERATION
(a) Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.
OK:






NG -- GO TO PROBLEM SYMPTOMS TABLE (STOP LIGHT SYSTEM)
OK -- Continue to next step.

2. CHECK BRK-LP RELAY
(a) Turn the engine switch off.




(b) Remove the BRK-LP relay from the engine room No. 3 relay block.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE BRK-LP RELAY
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - BATTERY)




(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - SKID CONTROL ECU)




(a) Disconnect the connector from the skid control ECU.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (STOOP LIGHT CONTROL RELAY - SKID CONTROL ECU)




(a) Disconnect the connector from the stop light control relay.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SKID CONTROL ECU