Stop Light Switch Circuit - Cruise Control System

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571/52: Stop Light Switch Circuit

DTC P0571/52 - Stop Light Switch Circuit

DESCRIPTION

When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control.
The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit.
The cancel condition occurs when positive battery voltage is applied to terminal STP.
When the brake is applied, positive battery voltage is normally applied to terminal STP of the ECM through the STOP fuse and the stop light switch assembly and the ECM turns the cruise control off.






WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: When troubleshooting in accordance with the PROBLEM SYMPTOMS TABLE, be sure to follow the table before replacing the ECM.

PROCEDURE

1. INSPECT STOP LIGHT SWITCH ASSEMBLY





(a) Disconnect the S8 stop light switch connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
OK -- Continue to next step.
2. CHECK WIRE HARNESS (STOP LIGHT SWITCH - BATTERY)





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






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
3. CHECK WIRE HARNESS (ECM - STOP LIGHT SWITCH)





(a) Reconnect the S8 stop light switch connector.
(b) Disconnect the E4 and E5 connectors from the ECM.
(c) Turn the ignition switch to the ON position.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE ECM