P0571

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571: Brake Switch "A" Circuit
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 cruise control system control of vehicle speed. 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 fuse and the stop light switch assembly, and the ECM cancels control of vehicle speed by the cruise control system.





WIRING DIAGRAM









INSPECTION PROCEDURE

NOTICE:
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.





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

Standard Voltage:





Text in Illustration





(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.





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

Standard Voltage:





Text in Illustration





(c) Reconnect the stop light switch assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - IG2 RELAY)
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:





Text in Illustration





(c) Reinstall the stop light switch assembly Installation.

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

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

(a) Disconnect the ECM connector.

(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 2AR-FE





for 2GR-FE





Standard Resistance (Check for Short):

for 2AR-FE





for 2GR-FE





Result:





(d) Reconnect the stop light switch assembly connector.

(e) Reconnect the ECM connector.

B -- REPLACE ECM Removal

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

A -- REPLACE ECM Removal