ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM, Diagnostic DTC:P0724

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

DESCRIPTION

The purpose of this circuit is to prevent the engine from stalling while driving in lock-up condition when brakes are suddenly applied.

When the brake pedal is depressed, this 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 the vehicle is driven in a STOP (less than 3 km/h (2 mph)) and GO (30 km/h (19 mph) or more) pattern 5 times. (2-trip detection logic).

  • Short in stop light switch signal circuit

  • Stop light switch

  • ECM

MONITOR DESCRIPTION

This DTC indicates that the stop light switch remains on. When the stop light switch remains ON during "stop and go" driving, the ECM interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC. The vehicle must stop (less than 3 km/h (2 mph)) and go (30 km/h (19 mph) or more) ten times for two driving cycles in order to detect a malfunction.

WIRING DIAGRAM

Click here.

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING DATA LIST (STP SIGNAL)


    1. DATA LIST

      Tech Tips

      Using the intelligent tester to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.


      1. Turn the ignition switch off.

      2. Connect the Intelligent Tester to the DLC3.

      3. Turn the ignition switch to the ON position.

      4. Turn on the tester.

      5. Select the item "Enter / Powertrain / Engine and ECT / Data List".

      6. Follow the instructions on the tester and read the Data List.

        Standard
        Item

        Measurement Item/

        Range (display)

        		 Normal Condition
        Stop Light Switch

        Stop light SW Status/

        ON or OFF

        • Brake Pedal is depressed: ON

        • Brake Pedal is released: OFF

        Note

        In the table above, the conditions listed under "Normal Condition" are reference conditions. Do not depend solely on these reference conditions when deciding whether a part is faulty or not.


    OK

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

    NG

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. A01BF15E75
      Text in Illustration
      *a

      Component without harness connected

      (Stop Light Switch Assembly)

      Remove the stop light switch assembly.

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

      Resistance
      Switch position Tester Connection Specified Condition
      Switch pin free 1 - 2 Below 1 Ω
      Switch pin pushed in ↑ 10 kΩ or higher
      Switch pin free 3 - 4 10 kΩ or higher
      Switch pin pushed in ↑ Below 1 Ω

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    OK

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


    1. A01BC97E82
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Install the stop light switch assembly.

    2. Measure the voltage according to the value(s) in the table below when the brake pedal is depressed and released.

      Voltage
      Condition Tester Connection Specified Condition
      Brake pedal is depressed B71-36 (STP) - Body ground 10 to 14 V
      Brake pedal is released ↑ Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM