CRUISE CONTROL SYSTEM(except 1ND-TV, 8NR-FTS), 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

E267669E28
E267669E31

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. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)

    1. E144327C05

      *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

      A1-2 - Body ground

      Always

      11 to 14 V

    3. Reconnect the stop light switch assembly connector.

    Result

    Proceed to

    OK

    NG
    NG

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

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)

    1. E144327C05

      *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

      A1-4 - Body ground

      Ignition switch ON

      11 to 14 V

    3. Reconnect the stop light switch assembly connector.

    Result

    Proceed to

    OK

    NG
    NG

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

    OK

  3. 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

  4. 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 (Check for Open)

      Table 1. for 1NR-FE, 1ZR-FAE, 1ZR-FE, 2ZR-FE

      Tester Connection

      Condition

      Specified Condition

      A50-9 (STP) - A1-1

      Always

      Below 1 Ω

      A50-10 (ST1-) - A1-3

      Always

      Below 1 Ω
      Table 2. for 1WW

      Tester Connection

      Condition

      Specified Condition

      A50-48 (STP) - A1-1

      Always

      Below 1 Ω

      A50-10 (ST1-) - A1-3

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Table 3. for 1NR-FE, 1ZR-FAE, 1ZR-FE, 2ZR-FE

      Tester Connection

      Condition

      Specified Condition

      A50-9 (STP) or A1-1 - Body ground

      Always

      10 kΩ or higher

      A50-10 (ST1-) or A1-3 - Body ground

      Always

      10 kΩ or higher
      Table 4. for 1WW

      Tester Connection

      Condition

      Specified Condition

      A50-48 (STP) or A1-1 - Body ground

      Always

      10 kΩ or higher

      A50-10 (ST1-) or A1-3 - Body ground

      Always

      10 kΩ or higher

      Result

      Proceed to

      OK

      NG

    4. Reconnect the stop light switch assembly connector.

    5. Reconnect the ECM connector.

    OK

    REPLACE ECM

    for 1NR-FE:Click here

    for 1ZR-FAE:Click here

    for 1ZR-FE:Click here

    for 2ZR-FE:Click here

    for 1WW:Click here

    NG

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