SFI SYSTEM, Diagnostic DTC:P0724

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

DESCRIPTION

The stop light switch is part of a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. This DTC indicates that the stop light switch assembly remains on. When the stop light switch assembly remains on during STOP and GO driving, the ECM interprets this as a fault in the stop light switch assembly. Then the ECM illuminates the MIL and stores the DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0724 Brake Switch "B" Circuit High The stop light switch remains on even when the vehicle repeats 5 cycles of STOP (less than 3 km/h [1.86 mph]) and GO (30 km/h [18.65 mph] or more) (2 trip detection logic).

  • Short in stop light switch assembly signal circuit

  • Stop light switch assembly

  • ECM

 Comes on DTC stored

MONITOR DESCRIPTION

This DTC indicates that the stop light switch assembly remains on. When the stop light switch assembly remains on during "STOP and GO" driving, the ECM interprets this as a fault in the stop light switch assembly. The ECM turns on MIL and stores the DTC. The vehicle must STOP (less than 3 km/h [1.86 mph]) and GO (30 km/h [18.65 mph] or more) 5 times during 2 driving cycles, in order to detect a malfunction.

MONITOR STRATEGY

Required Sensors/Components (Main) Stop light switch assembly
Required Sensors/Components (Related) Speed sensor
Frequency of Operation Continuous

CONFIRMATION DRIVING PATTERN

B003KD4E59

  1. Connect the GTS to the DLC3.

  2. Turn the engine switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the GTS on [A].

  6. Wait 5 seconds.

  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].

  8. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  10. Input the DTC: P0724.

  11. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [C] through [E].

  12. Start the engine [C].

  13. Accelerate the vehicle to 30 km/h (18.65 mph) or more, depress the brake pedal and decelerate the vehicle to 3 km/h (1.86 mph) or less [D]. Repeat step [D] 5 times.

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

  14. Check the DTC judgment result [E].

WIRING DIAGRAM

Refer to DTC P0504.

Click here

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

Tech Tips


  • 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 help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

  • Using the GTS, the Data List item "Stop Light Switch" and "ST1" can be read.

    Click here

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 / Primary / Stop Light Switch.


      Powertrain > Engine > Data List
      Tester Display
      Stop Light Switch

    5. Read the values displayed on the GTS.

      OK
      GTS Display Measurement Item/Range (display) Normal Condition
      Stop Light Switch Stop light switch status: ON or OFF

      • ON: Brake pedal depressed

      • OFF: Brake pedal released
      Result
      Proceed to
      OK
      NG

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

  2. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the stop light switch installation.

      Click here

      OK
      Stop light switch is installed correctly.
      Result
      Proceed to
      OK
      NG

    NG

    SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY Click here

    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
      Tester Connection Condition Specified Condition
      A64-3 (L) - G143-10 (STP) Always Below 1 Ω
      A64-3 (L) or G143-10 (STP) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)

    OK

  4. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Inspect the stop light switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here