Cruise Control System

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571: Brake Switch "A" Circuit

DTC P0571 - Brake Switch "A" Circuit

DESCRIPTION

When the brake pedals is depressed, the stop light switch 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 cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the ECM through the STOP SW fuse and the stop light switch, and the ECM turns the cruise control off.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT STOP LIGHT SWITCH





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






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





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






NG -- REPAIR OR REPLACE WIRE HARNESS AND CONNECTOR
OK -- Continue to next step.
3. CHECK ECM





(a) Reconnect the stop light switch connector.
(b) Disconnect the A6 connectors from the ECM (for 1UR-FSE.
(c) Disconnect the A6 and A7 connectors from the ECM (for 2GR-FSE).
(d) Turn the engine switch on (IG).
(e) Measure the voltage according to the value(s) in the table below.
Standard voltage (for 1UR-FSE):






Standard voltage (for 2GR-FSE):





HINT:
- *1: for 1UR-FSE
- *2: for 2GR-FSE

NG -- REPAIR OR REPLACE WIRE HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
OK -- REPLACE ECM