SFI SYSTEM, Diagnostic DTC:P0724

DTC Code DTC Name
P0724 Brake Switch "B" Circuit High

DESCRIPTION

The stop light switch assembly is a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly.

The purpose of this circuit is to prevent the engine from stalling while driving with the lock-up torque converter clutch on when the brakes are suddenly applied.

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in progress.

DTC No. DTC Detection Condition Trouble Area
P0724 The stop light switch remains on even when vehicle is driven in a GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) pattern 5 times (2 trip detection logic).

  • Short in stop light switch signal circuit

  • Stop light switch assembly

  • ECM

WIRING DIAGRAM

Refer to DTC P0504 Click here.

CAUTION / NOTICE / HINT

Tech Tips


  • Using the GTS to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

  • Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was moving or stationary, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. READ VALUE USING GTS (STOP LIGHT SWITCH)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.

    5. Read the value displayed on the GTS when the brake pedal is depressed and released.

      OK
      Brake Pedal Display
      Released OFF
      Depressed ON

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

  2. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the stop light switch assembly installation Click here.

      OK
      Stop light switch assembly is installed correctly.

    NG

    SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY

    OK

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


    1. Disconnect the stop light switch assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      for Automatic Transmission
      Tester Connection Condition Specified Condition
      A85-2 (L) - G56-35 (STP) Always Below 1 Ω
      A85-4 (L) - G56-34 (ST1-) Always Below 1 Ω
      for Manual Transmission
      Tester Connection Condition Specified Condition
      A85-2 (L) - G56-18 (STP) Always Below 1 Ω
      A85-4 (L) - G55-8 (ST1-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      for Automatic Transmission
      Tester Connection Condition Specified Condition
      A85-2 (L) or G56-35 (STP) - Body ground Always 10 kΩ or higher
      A85-4 (L) or G56-34 (ST1-) - Body ground Always 10 kΩ or higher
      for Manual Transmission
      Tester Connection Condition Specified Condition
      A85-2 (L) or G56-18 (STP) - Body ground Always 10 kΩ or higher
      A85-4 (L) or G55-8 (ST1-) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Inspect the stop light switch assembly Click here.


    OK

    REPLACE ECM Click here

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here