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 occurs 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

A0136U6E01

INSPECTION PROCEDURE

Note

After replace 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 ASSEMBLY


    1. A0138EQE02

      Measure the resistance between each pair of the terminals.

      Standard resistance
      Switch Position Tester Connection Specified Condition
      Switch pin free 1 - 2 Below 1 Ω
      Switch pin free 3 - 4 10 kΩ or higher
      Switch pin pushed in 1 - 2 10 kΩ or higher
      Switch pin pushed in 3 - 4 Below 1 Ω

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    OK

  3. CHECK STP AND ST1- SIGNAL


    1. A0137ISE01

      Connect the intelligent tester II to the DLC3.

    2. Turn the engine switch ON (IG) and turn the intelligent tester II ON.

    3. Select the following menu items: Powertrain / Engine and ECT / Data List / Stop Light SW.

    4. Check the result.

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

    5. Measure the voltage between the specified terminals of the B25 ECM connectors and body ground.

      Standard voltage
      Tester Connection Brake Pedal Specified Condition
      ST1 - (B25-60) - Body ground Depressed Below 1.5 V
      ST1 - (B25-60) - Body ground Released 7.5 to 14 V

    OK

    GO TO "CHECK FOR INTERMITTENT PROBLEMS"

    NG

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


    1. A01378EE01

      Disconnect the S17 stop light switch connector.

    2. Disconnect the B25 ECM connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      Stop light switch (S17-1) - STP (B25-74) Below 1 Ω
      Stop light switch (S17-4) - ST1- (B25-66) Below 1 Ω

    4. Reconnect the stop light switch connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE ECM