Dynamic Laser Cruise Control System

CRUISE CONTROL: DYNAMIC LASER 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. READ VALUE ON INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch on, and turn the intelligent tester main switch on.
(c) Check the DATA LIST for proper functioning of the stop light switch.

ECM (Cruise control):





OK:
When the brake pedal is operated, the display changes as shown above.
OK -- REPLACE ECM
NG -- Continue to next step.
2. INSPECT STOP LIGHT SWITCH





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






NG -- REPLACE STOP LIGHT SWITCH
OK -- Continue to next step.
3. CHECK WIRE HARNESS (STOP LIGHT SWITCH - BATTERY)





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK ECM





(a) Reconnect the stop light switch connector.
(b) Disconnect the E5 connector from the ECM.
(c) Turn the ignition switch on.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - ECM)
OK -- REPLACE ECM