SFI SYSTEM, Diagnostic DTC:P0724

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

DESCRIPTION

The stop light switch assembly 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 the ECM stores the DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0724

Brake Switch "B" Circuit High

Stop light switch assembly remains on even when 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 the 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.

CONFIRMATION DRIVING PATTERN

A199312E33

  1. Connect the GTS to the DLC3.

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

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

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

  5. Turn the ignition switch to ON 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.

    Tip:

    • 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
    Tip:

    • 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, and then 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.

Tip:

  • 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 hereClick here).

PROCEDURE

  1. READ VALUE USING GTS (STOP LIGHT SWITCH)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

      Powertrain > Engine and ECT > 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 assembly 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 assembly installation (Click here).

      OK

      Stop light switch assembly is installed correctly.

    Result

    Proceed to

    OK

    NG
    NG

    SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY

    (Click here)

    OK

  3. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. Inspect the stop light switch assembly (Click here).

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    (Click here)

    OK

  4. CHECK TERMINAL VOLTAGE (STP VOLTAGE)

    1. Disconnect the ECM connector.

    2. A298902C02

      *a

      Brake Pedal Depressed

      *b

      Brake Pedal Released

      *c

      Front view of wire harness connector

      (to ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Brake Pedal Operation

      Specified Condition

      A62-9 (STP) - Body ground

      Released

      Below 1.5 V

      Depressed

      7.5 to 14 V

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    (Click hereClick here)

    NG

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