SFI SYSTEM (w/ Electronic Throttle Control System), Diagnostic DTC:P0571

DTC Code DTC Name
P0571 Brake Switch "A" Circuit

DESCRIPTION

The stop light switch has a duplex system (signals STP and ST1-) to memorize the abnormality when the signals of depressing and releasing the brake pedal are detected simultaneously.

Tech Tips

Normal condition is as shown in the table.

Signal Brake Pedal Released In Transition Brake Pedal Depressed
STP OFF ON ON
ST1- ON ON OFF
DTC No. DTC Detection Condition Trouble Area
P0571

All of the following conditions are met: (1 trip detection logic)


  • Ignition switch ON

  • The following will repeatedly occur 10 times.


    • STP signal is OFF when the ST1- signal is OFF.

  • Short in stop light switch signal circuit

  • Stop light switch

  • ECM

WIRING DIAGRAM

A0136U6E02

INSPECTION PROCEDURE

Note

After replacing the ECM, perform electronic throttle learning Click here.

PROCEDURE


  1. CHECK STOP LIGHT OPERATION


    1. Check if the stop lights come on and go off normally when the brake pedal is depressed and released.

      OK
      The stop lights come ON when you depress the brake pedal.

    NG

    REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT

    OK

  2. INSPECT STOP LIGHT SWITCH


    1. A0138EQE02

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch pin not pushed Below 1 Ω
      Switch pin pushed 10 kΩ or higher
      3 - 4 Switch pin not pushed 10 kΩ or higher
      Switch pin pushed Below 1 Ω

    NG

    REPLACE STOP LIGHT SWITCH Click here

    OK

  3. CHECK STP AND ST1- SIGNAL


    1. A0136S6E01

      Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light SW.

    4. Check the result.

      OK
      Brake Pedal Specified Condition
      Depressed STP Signal ON
      Released STP Signal OFF

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

      Standard Voltage
      Tester Connection Brake Pedal Specified Condition
      B26-7 (ST1-) - Body ground Depressed Below 1.5 V
      B26-7 (ST1-) - Body ground Released 11 to 14 V
      B26-31 (STP) - Body ground Depressed 11 to 14 V
      B26-31 (STP) - Body ground Released Below 1.5 V

    NG

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM) Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

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


    1. A01361ZE01

      Disconnect the stop light switch connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A17-1 - B26-31 (STP) Always Below 1 Ω
      A17-4 - B26-7 (ST1-) Always Below 1 Ω

    4. Reconnect the stop light switch connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here