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

A01QSSLE34
for 2AR-FE
*a from Battery
*b STOP
*c from IG2 Relay
*d Stop Light Switch Assembly
A01QSSLE35
for 3ZR-FAE, 3ZR-FE
*a from Battery
*b STOP
*c from IG2 Relay
*d Stop Light Switch Assembly
A01QSSLE39
for 2AD-FHV, 2AD-FTV
*a from Battery
*b STOP
*c from IG2 Relay
*d Stop Light Switch Assembly
A01QSSLE37
for 2WW
*a from Battery
*b STOP
*c from IG2 Relay
*d Stop Light Switch Assembly

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. Disconnect the stop light switch assembly connector.

    2. A01QUKKC07
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A77-7 (B) - Body ground Always 11 to 14 V
      A77-6 (B) - Body ground Ignition switch ON 11 to 14 V
      A77-6 (B) - Body ground Ignition switch off Below 1 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the ECM connector.

    2. A01QOV4C22
      *a

      Front view of wire harness connector

      (to ECM)

      for 2AR-FE:

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A62-24 (ST1-) - Body ground Ignition switch ON, brake pedal depressed Below 1.5 V
      Ignition switch ON, brake pedal released 7.5 to 14 V
      A62-11 (STP) - Body ground Brake pedal depressed 7.5 to 14 V
      Brake pedal released Below 1.5 V
    3. A01QOV4C23
      *a

      Front view of wire harness connector

      (to ECM)

      for 3ZR-FAE, 3ZR-FE:

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A62-10 (ST1-) - Body ground Ignition switch ON, brake pedal depressed Below 1.5 V
      Ignition switch ON, brake pedal released 7.5 to 14 V
      A62-9 (STP) - Body ground Brake pedal depressed 7.5 to 14 V
      Brake pedal released Below 1.5 V
    4. A01QQRGC03
      *a

      Front view of wire harness connector

      (to ECM)

      for 2AD-FHV, 2AD-FTV:

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A61-34 (ST1-) - Body ground Ignition switch ON, brake pedal depressed 0 to 1.5 V
      Ignition switch ON, brake pedal released 7.5 to 14 V
      A61-35 (STP) - Body ground Brake pedal depressed 7.5 to 14 V
      Brake pedal released 0 to 1.5 V
    5. A01QOV4C24
      *a

      Front view of wire harness connector

      (to ECM)

      for 2WW:

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A62-10 (ST1-) - Body ground Ignition switch ON, brake pedal depressed 0 to 1.5 V
      Ignition switch ON, brake pedal released 7.5 to 14 V
      A62-48 (STP) - Body ground Brake pedal depressed 7.5 to 14 V
      Brake pedal released 0 to 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK STOP LIGHT SWITCH ASSEMBLY


    1. Temporarily replace the stop light switch assembly with a new or normally functioning one.

      Click here

    2. Clear the DTCs.

      Click here


      1. for 2AD-FTV, 2AD-FHV:


        Powertrain > Cruise Control > Clear DTCs

      2. for 2AR-FE, 3ZR-FE, 3ZR-FAE:


        Powertrain > Cruise Control > Clear DTCs

      3. for 2WW:


        Powertrain > Cruise Control > Clear DTCs

    3. Check for DTCs.

      Click here


      1. for 2AD-FTV, 2AD-FHV:


        Powertrain > Cruise Control > Trouble Codes

      2. for 2AR-FE, 3ZR-FE, 3ZR-FAE:


        Powertrain > Cruise Control > Trouble Codes

      3. for 2WW:


        Powertrain > Cruise Control > Trouble Codes
      Result
      Result Proceed to
      DTC is not output A
      DTC P0571 is output B

    A

    END (STOP LIGHT SWITCH ASSEMBLY WAS DEFECTIVE)

    B

    REPLACE ECM for 2AD-FHV: Click here
    REPLACE ECM for 2AD-FTV: Click here
    REPLACE ECM for 2AR-FE: Click here
    REPLACE ECM for 3ZR-FAE: Click here
    REPLACE ECM for 3ZR-FE: Click here
    REPLACE ECM for 2WW: Click here