Stop Light Switch Circuit - Cruise Control System

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0571/52: Stop Light Switch Circuit
P0571/52 - Stop Light Switch Circuit

DESCRIPTION

While driving with the cruise control, if the ECM detects that the brake pedal is depressed, the cruise control operation will be canceled. The stop light switch sends brake pedal status signals to the ECM. When the brake pedal is not depressed, terminal ST1- is equal to the positive (+) battery voltage and terminal STP is below 1 V. When the brake pedal is depressed, the ECM cancels cruise control operation. The ECM outputs this DTC when the voltage of terminals ST1- and STP are both below 1 V for 0.5 seconds or more at the same time. 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. INSPECT FUSE (STOP, IGN, IG2)

(a) Remove the STOP and IGN fuses from the instrument panel junction block.

(b) Remove the IG2 fuse from the engine room No. 1 relay block.

(c) Measure the resistance of the fuses.

Standard resistance:

Below 1 Ohms

NG -- REPLACE FUSE
OK -- Continue to next step.

2. INSPECT IG2 RELAY





(a) Remove the IG2 relay from the instrument panel junction block.

(b) Measure the resistance of the relay.

Standard resistance:





NG -- REPLACE IG2 RELAY
OK -- Continue to next step.

3. INSPECT STOP LIGHT SWITCH





(a) Remove the stop light switch.

(b) Measure the resistance of the switch.

Standard resistance:





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

4. CHECK WIRE HARNESS (SWITCH - BATTERY)





(a) Disconnect the A3 switch connector.

(b) Measure the voltage of the wire harness side connector.

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. CHECK WIRE HARNESS (ECM - BATTERY)





(a) Disconnect the A9 ECM connector.

(b) Turn the ignition switch ON.

(c) Measure the voltage of the wire harness side connector.

Standard voltage:

for 2GR-FE





for 2AR-FE





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR

OK -- REPLACE ECM