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 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. Cruise control cancellation 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 fuse and the stop light switch assembly, and the ECM turns the cruise control off.





WIRING DIAGRAM









INSPECTION PROCEDURE
HINT: Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)




(a) Disconnect the stop light switch assembly connector.

Text in Illustration





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





(c) Reconnect the stop light switch assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)
OK -- Continue to next step.

2. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)




(a) Disconnect the stop light switch assembly connector.

Text in Illustration





(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





(d) Reconnect the stop light switch assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IGN FUSE)
OK -- Continue to next step.

3. INSPECT STOP LIGHT SWITCH ASSEMBLY




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





(c) Reinstall the stop light switch assembly Installation.

NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)




(a) Disconnect the ECM connector.

Text in Illustration





(b) Disconnect the stop light switch assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):

For 1AR-FE





For 2GR-FE





Standard Resistance (Check for Short):

For 1AR-FE





For 2GR-FE





(d) Reconnect the stop light switch assembly connector.
(e) Reconnect the ECM connector.
HINT:
- *3: for 1AR-FE
- *4: for 2GR-FE

Result:





C -- REPLACE ECM
B -- REPLACE ECM
A -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)