CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

DTC Code DTC Name
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 applied to terminal STP of the ECM through the STOP fuse and the stop light switch, and the ECM turns the cruise control off.

DTC Code DTC Detection Condition Trouble Area
P0571 When the voltage of the STP terminal and the ST1- terminal of the ECM is below 1 V for 0.5 second or more.

  • Stop light switch

  • Stop light switch circuit

  • ECM

WIRING DIAGRAM

A01ESCBE06
A01ESCBE05

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)


    1. Using the intelligent tester, read the Data List.

      Cruise Control
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light SW M-CPU Stop light switch signal (Main CPU) / ON or OFF

      ON: Brake pedal depressed

      OFF: Brake pedal released

      		 -
      OK
      Normal conditions listed above are displayed.
      Result
      Result Proceed to
      NG A
      OK (for 1UR-FE) B
      OK (for 3UR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

  2. INSPECT STOP LIGHT SWITCH

    A01EQQKE01

    1. Remove the stop light switch Click here for LHD, Click here for RHD).

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Pin pushed 10 kΩ or higher
      Pin not pushed Below 1 Ω
      3 - 4 Pin pushed Below 1 Ω
      Pin not pushed 10 kΩ or higher
      Result
      Result Proceed to
      OK A

      NG

      (for LHD)

      		 B

      NG

      (for RHD)

      		 C

    B

    REPLACE STOP LIGHT SWITCH Click here

    C

    REPLACE STOP LIGHT SWITCH Click here

    A

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

    A01EOQJE01

    1. Disconnect the A30 stop light switch connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A30-2 - Body ground Always 11 to 14 V
      A30-4 - Body ground Engine switch on (IG)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    A01EPECE05

    1. A01EPECE02

      for 1UR-FE:


      1. Disconnect the A30 stop light switch connector.

      2. Disconnect the A53 ECM connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        A30-1 - A53-36 (STP) Always Below 1 Ω
        A30-1 - Body ground Always 10 kΩ or higher
        A30-3 - A53-35 (ST1-) Always Below 1 Ω
        A30-3 - Body ground Always 10 kΩ or higher

    2. for 3UR-FE:


      1. Disconnect the A30 stop light switch connector.

      2. Disconnect the A38*1 or A53*2 ECM connector.


        • *1: for LHD

        • *2: for RHD

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

        Standard Resistance
        for LHD
        Tester Connection Condition Specified Condition
        A30-1 - A38-36 (STP) Always Below 1 Ω
        A30-1 - Body ground Always 10 kΩ or higher
        A30-3 - A38-35 (ST1-) Always Below 1 Ω
        A30-3 - Body ground Always 10 kΩ or higher
        for RHD
        Tester Connection Condition Specified Condition
        A30-1 - A53-36 (STP) Always Below 1 Ω
        A30-1 - Body ground Always 10 kΩ or higher
        A30-3 - A53-35 (ST1-) Always Below 1 Ω
        A30-3 - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      NG A
      OK (for 1UR-FE) B
      OK (for 3UR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR