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

A01TAYSE09
for 1NR-FE, 1ZR-FAE, 1ZR-FE, 2ZR-FE
*a from IGN Fuse
*b from STOP Fuse
*c Stop Light Switch Assembly
A01TAYSE07
for 1AD-FTV
*a from IGN Fuse
*b from STOP Fuse
*c Stop Light Switch Assembly

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE)


    1. A01TBW2C05
      *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. A01TBW2C05
      *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)
      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
      for 1AD-FTV
      Tester Connection Condition Specified Condition
      A118-35 (STP) - A1-1 Always Below 1 Ω
      A118-34 (ST1-) - A1-3 Always Below 1 Ω
      Standard Resistance (Check for Short)
      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
      for 1AD-FTV
      Tester Connection Condition Specified Condition
      A118-35 (STP) or A1-1 - Body ground Always 10 kΩ or higher
      A118-34 (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
    REPLACE ECM for 1ZR-FAE: Click here
    REPLACE ECM for 1ZR-FE: Click here
    REPLACE ECM for 2ZR-FE: Click here
    REPLACE ECM for 1AD-FTV: Click here

    NG

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