P0571

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571: Stop Light Switch Circuit Malfunction
P0571 - Stop Light Switch Circuit Malfunction

DESCRIPTION

The cruise control system cancels cruising when the ECM detects that the brake pedal is depressed while cruise control driving. The stop light switch sends signals to the ECM according to the brake pedal conditions. When the brake pedal is free, terminal ST1- is the positive (+) battery voltage, and terminal STP voltage is below 1 V. While depressing the brake pedal, terminal ST1- is below 1 V, and STP is positive (+) battery voltage. Under braking, the ECM cancels cruise control as one of the manual cancel functions.

The ECM outputs this trouble code when the voltage of terminals ST1- and STP are both below 1 V for 0.5 seconds or more at the same moment.

The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK FOR DTC (VEHICLE STABILITY CONTROL SYSTEM)

(a) Check for DTCs in Vehicle Stability Control System.

* for Hydraulic Booster Type Vehicle Stability Control System (for Hydraulic Brake Booster).

* for Vacuum Booster Type Vehicle Stability Control System (for Vacuum Brake Booster).

OK:

DTC is not output.

Result





C -- GO TO DTC CHART

B -- GO TO DTC CHART
A -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)

(a) Disconnect the S10 connector from the stop light switch.





(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.

3. INSPECT STOP LIGHT SWITCH

(a) Turn the ignition switch off.





(b) Remove the stop light switch.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(d) Reinstall the stop light switch.

Result





C -- REPLACE STOP LIGHT SWITCH

B -- INSPECT ECM
A -- Continue to next step.

4. INSPECT ECM

(a) Disconnect the E13 and E14 ECM connector.





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

Standard Voltage:





(c) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal

5. INSPECT ECM

(a) Disconnect the E7 and E8 ECM connector.





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

Standard Voltage:





(c) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal