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DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

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DTC Code DTC Name
P0571 Stop Light Switch Circuit Malfunction
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DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. Upon receiving the signal, the ECM cancels cruise control. Even if there is a malfunction in the stop light signal circuit while cruise control is in operation, normal driving is maintained due to a fail-safe function.

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

DTC Code DTC Detection Condition Trouble Area
P0571 The voltages of terminals ST1- and STP of the ECM are both below 1 V for 0.5 seconds or more.

  • Stop light switch circuit

  • Stop light switch assembly

  • ECM
A01DQKME02
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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

  • When the ECM is replaced with a new one, initialization must be performed (Click here).

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

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)


    1. A01DMNDE09

      Disconnect the A85 switch connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A85-1 (B) - Body ground Always 11 to 14 V
      A85-5 (B) - Body ground Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A85-3 (GND) - Body ground Always Below 1 Ω
      Table 1. Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

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    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)


    1. Disconnect the A85 switch connector.

    2. Disconnect the G55*1 and G56*1 or G57*2 ECM connectors.


      • *1: for 1GR-FE

      • *2: for 1KD-FTV

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

      Standard Resistance
      Table 2. for 1GR-FE
      Tester Connection Switch Condition Specified Condition
      A85-4 (L) - G55-8 (ST1-) Always Below 1 Ω
      A85-2 (L) - G56-18 (STP)
      A85-4 (L) - Body ground Always 10 kΩ or higher
      A85-2 (L) - Body ground
      Table 3. for 1KD-FTV
      Tester Connection Switch Condition Specified Condition
      A85-4 (L) - G57-9 (ST1-) Always Below 1 Ω
      A85-2 (L) - G57-8 (STP)
      A85-4 (L) - Body ground Always 10 kΩ or higher
      A85-2 (L) - Body ground

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    CHECK STOP LIGHT SWITCH ASSEMBLY


    1. Temporarily replace the stop light switch with a new or normally functioning one (Click here).

    2. Clear the DTCs (Click here).

    3. Check for DTCs (Click here).

      Table 4. Result
      Result Proceed to
      OK A
      NG (for 1GR-FE) B
      NG (for 1KD-FTV) C

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    END (STOP LIGHT SWITCH IS DEFECTIVE)

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPLACE ECMClick here

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    REPLACE ECMClick here