P0571

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

DTC P0571 - Brake Switch "A" Circuit

DESCRIPTION

When the brake pedal 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 FUSES (STOP AND IGN)





(a) Remove the STOP and IGN fuses from the main body ECU.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Reinstall the STOP and IGN fuses.
NG -- REPLACE FUSE
OK -- Continue to next step.
2. READ VALUE USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the tester on.
(d) Enter the following menus: Powertrain / Cruise Control / Data List.
(e) According to the display on tester, read the "DATA LIST".

Cruise control





OK:
Normal conditions listed above are displayed.
NG -- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)
OK -- REPLACE ECM
3. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)





(a) Disconnect the A11 stop light switch connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(c) Reconnect the stop light switch connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. INSPECT STOP LIGHT SWITCH





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





(c) Reinstall the stop light switch.
NG -- REPLACE STOP LIGHT SWITCH
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)





(a) Disconnect the A11 stop light switch connector.
(b) Disconnect the A21 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(d) Reconnect the stop light switch connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM