CRUISE CONTROL SYSTEM(for 1ND-TV without Driving support ECU), 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. When the ECM receives this signal, it cancels cruise control system control of vehicle speed. 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 normally applied to terminal STP of the ECM through the STOP fuse and the stop light switch assembly, and the ECM cancels control of vehicle speed by the cruise control system.

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 sec. or more.

  • Stop light switch assembly

  • Stop light switch circuit

  • ECM

WIRING DIAGRAM

A315471E09
E267669E38

CAUTION / NOTICE / HINT

Note:

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

  • Before replacing the ECM, refer to Service Bulletin.

PROCEDURE

  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)

    1. E233306C75

      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      for TMMT Made:

      1. Disconnect the A176 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

        A176-7 (B) - A176-2 (GND)

        Always

        11 to 14 V

        A176-6 (B) - A176-2 (GND)

        Ignition switch ON

        11 to 14 V
    2. E144327C28

      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      for TMUK Made:

      1. Disconnect the A1 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

        A1-2 - Body ground

        Always

        11 to 14 V

        A1-4 - Body ground

        Ignition switch ON

        11 to 14 V

    Result

    Result

    Proceed to

    OK (for TMMT Made)

    A

    OK (for TMUK Made)

    B

    NG

    C
    B

    INSPECT STOP LIGHT SWITCH ASSEMBLYClick here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY OR IG2 RELAY)

    A

  2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)

    1. Disconnect the A176 stop light switch assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A176-2 (GND) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)

    OK

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

    1. Disconnect the ECM connector.

    2. Disconnect the 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

      A169-48 (STP) - A176-3 (L)

      Always

      Below 1 Ω

      A169-38 (ST1-) - A176-5 (L)

      Always

      Below 1 Ω

      A169-48 (STP) or A176-3 (L) - Body ground

      Always

      10 kΩ or higher

      A169-38 (ST1-) or A176-5 (L) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)

    OK

  4. REPLACE STOP LIGHT SWITCH ASSEMBLY

    1. Replace the stop light switch assembly.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  5. CHECK FOR DTCs (CRUISE CONTROL SYSTEM)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Click here

      Powertrain > Cruise Control > Clear DTCs

    5. Perform the following to make sure that the DTC detection conditions are met.

      Tip:

      If the detection conditions are not met, the malfunction cannot be detected.

      1. Turn the cruise control system on using the cruise control switch (ON-OFF button).

    6. Check for DTCs.

      Click here

      Powertrain > Cruise Control > Trouble Codes

    Result

    Result

    Proceed to

    DTCs are not output

    A

    DTC P0571 is output

    B
    A

    END (STOP LIGHT SWITCH ASSEMBLY WAS DEFECTIVE)

    B

    REPLACE ECM

    Click here

  6. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. Inspect the stop light switch assembly.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    Click here

    OK

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

    1. Disconnect the A169 ECM connector.

    2. Disconnect the A1 stop light switch assembly connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      A169-48 (STP) - A1-1

      Always

      Below 1 Ω

      A169-38 (ST1-) - A1-3

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      A169-48 (STP) or A1-1 - Body ground

      Always

      10 kΩ or higher

      A169-38 (ST1-) or A1-3 - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. Reconnect the ECM connector.

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)