P0571

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

DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the hybrid vehicle control ECU.

Upon receiving the signal, the hybrid vehicle control ECU cancels the cruise control system. Even if there is a malfunction in the stop light signal circuit while the cruise control is in operation, normal driving is maintained due to a fail-safe function. Cruise control is canceled when positive battery voltage is applied to terminal STP.

When the brake pedal is depressed, positive voltage is applied to terminal STP of the hybrid vehicle control ECU through the STOP fuse and the stop light switch, and the hybrid vehicle control ECU cancels the cruise control.

When the brake pedal is released, positive voltage is applied to terminal ST1- of the hybrid vehicle control ECU through the ECU-IG fuse and the stop light switch, and the hybrid vehicle control ECU operates the cruise control.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

(a) Check the Data List for proper functioning of the stop light switch Cruise Control System.

Cruise Control





OK:

Display changes according to brake pedal operation described in the above table.

NG -- INSPECT FUSE (STOP, ECU-IG)

OK -- REPLACE HYBRID VEHICLE CONTROL ECU Removal

2. INSPECT FUSE (STOP, ECU-IG)

(a) Remove the STOP fuse from the main body ECU.

(b) Remove the ECU-IG fuse from the engine room No. 2 junction block.

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

Standard resistance:





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

3. INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Remove the stop light switch Removal.





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

Standard resistance:





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

4. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BATTERY)

(a) Disconnect the A75 and A76 ECU connectors.





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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE HYBRID VEHICLE CONTROL ECU Removal