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

E270488E01

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. E270489C01

      *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

    for 2AD-FHV:Click here

    for 2AD-CCo, 2AD-DPF:Click here

    for 2AR-FE:Click here

    for 3ZR-FAE:Click hereClick here

    for 3ZR-FE:Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR