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 than 1 V for 0.5 second. or more.

  • Stop light switch

  • Stop light switch circuit

  • ECM

WIRING DIAGRAM

A01X8FDE04

PROCEDURE


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


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

      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

      OK

      (for 1GR-FE)

      		 A

      OK

      (for 1UR-FE)

      		 B

      OK

      (for 3UR-FE)

      		 C

      OK

      (for 1VD-FTV)

      		 D
      NG E

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    D

    REPLACE ECM Click here

    E

  2. INSPECT STOP LIGHT SWITCH

    A01X5Y7E01
    *1 Component without harness connected: (Stop Light Switch)
    *2 Pin pushed
    *3 Pin released

    1. Remove the stop light switch Click here.

    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)

    A01XBFDE02
    *1 Front view of wire harness connector: (to Stop Light Switch)

    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 Condition Specified Condition
      A30-2 - Body ground Always 11 to 14 V
      A30-4 - Body ground Ignition switch ON

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK ENGINE TYPE


    1. Check the engine type.

      Engine Type
      Engine type Proceed to
      for 1GR-FE, 1UR-FE, 3UR-FE, 1VD-FTV (w/o DPF) A
      for 1VD-FTV (w/ DPF) B

    B

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM) Click here

    A

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

    A01X6BAE01

    1. Disconnect the A30 stop light switch connector.

    2. Disconnect the A38*1 or A52*2 ECM connector.

      Tech Tips


      • *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 - A52-36 (STP) Always Below 1 Ω
      A30-1 - Body ground Always 10 kΩ or higher
      A30-3 - A52-35 (ST1-) Always Below 1 Ω
      A30-3 - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to

      OK

      (for 1GR-FE)

      		 A

      OK

      (for 1UR-FE)

      		 B

      OK

      (for 3UR-FE)

      		 C

      OK

      (for 1VD-FTV, w/o DPF)

      		 D
      NG E

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    D

    REPLACE ECM Click here

    E

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

    A01X6BAE02

    1. Disconnect the A30 stop light switch connector.

    2. Disconnect the A38*1 or A52*2 ECM connector.

      Tech Tips


      • *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 - A38-13 (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 - A52-13 (STP) Always Below 1 Ω
      A30-1 - Body ground Always 10 kΩ or higher
      A30-3 - A52-35 (ST1-) Always Below 1 Ω
      A30-3 - Body ground Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR