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 assembly sends a signal to the ECM. Upon receiving the signal, the ECM 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 voltage is applied to terminal STP.

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

When the brake pedal is released, positive voltage is applied to terminal ST1- of the ECM through the IGN fuse and the stop light switch assembly, and the ECM operates the cruise control.

DTC No. Detection Item DTC Detection Condition Trouble Area
P0571 Brake Switch "A" Circuit When voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 seconds or more

  • Stop light switch assembly

  • ECM

  • Harness or connector

WIRING DIAGRAM

A01KCTAE01

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


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


    1. A01KAWZC01
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A5-2 - Body ground Always 11 to 14 V
      A5-4 - Body ground Ignition switch ON 11 to 14 V
      A5-4 - Body ground Ignition switch off Below 1 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Remove the stop light switch assembly.

      Click here

    2. Inspect the stop light switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

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


    1. for 1AD-FTV, 2AD-FHV, 2AD-CCo, 2AD-DPF


      1. Disconnect the A61 ECM connector.

      2. Disconnect the A5 stop light switch assembly connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        A61-34 (ST1-) - A5-3 Always Below 1 Ω
        A61-35 (STP) - A5-1 Always Below 1 Ω
        A61-34 (ST1-) or A5-3 - Body ground Always 10 kΩ or higher
        A61-35 (STP) or A5-1 - Body ground Always 10 kΩ or higher

    2. for 2AR-FE


      1. Disconnect the A62 ECM connector.

      2. Disconnect the A5 stop light switch assembly connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        A62-1 (STP) - A5-1 Always Below 1 Ω
        A62-24 (ST1-) - A5-3 Always Below 1 Ω
        A62-1 (STP) or A5-1 - Body ground Always 10 kΩ or higher
        A62-24 (ST1-) or A5-3 - Body ground Always 10 kΩ or higher

    3. for 3AR-FAE, 3ZR-FE


      1. Disconnect the A62 ECM connector.

      2. Disconnect the A5 stop light switch assembly connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        A62-9 (STP) - A5-1 Always Below 1 Ω
        A62-10 (ST1-) - A5-3 Always Below 1 Ω
        A62-9 (STP) or A5-1 - Body ground Always 10 kΩ or higher
        A62-10 (ST1-) or A5-3 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM for 1AD-FTV: Click here
    REPLACE ECM for 2AD-FHV: Click here
    REPLACE ECM for 2AD-CCo, 2AD-DPF: Click here
    REPLACE ECM for 2AR-FE: Click here
    REPLACE ECM for 3ZR-FAE: Click here
    REPLACE ECM for 3ZR-FE: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR