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 stores the DTC.

DTC No. DTC Detection Condition Trouble Area
P0724 The stop light switch assembly 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 signal circuit

  • Stop light switch assembly

  • ECM

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

Related DTCs P0724: Brake pedal position switch verify switch input
Required Sensors/Components (Main) Stop light switch assembly
Required Sensors/Components (Related) Speed sensor
Frequency of Operation Continuous
Duration GO and STOP 5 times
MIL Operation 2 driving cycles
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored None
Battery voltage 8 V or higher
Engine switch On (IG)
Starter Off
GO: Vehicle speed 30 km/h (18.65 mph) or more
STOP: Vehicle speed Less than 3 km/h (1.86 mph)

TYPICAL MALFUNCTION THRESHOLDS

Brake pedal position switch On stuck

CONFIRMATION DRIVING PATTERN

A011TE2E34

  1. Connect the Techstream to the DLC3.

  2. Turn the engine switch on (IG) and turn the Techstream 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 Techstream on [A].

  6. Wait 5 seconds.

  7. Enter the following menus: Powertrain / Engine / 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 / Utility / All Readiness.

  10. Input the DTC: P0724.

  11. Check the DTC judgment result.

    Techstream 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].

  15. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips

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

    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0504 Click here.

INSPECTION PROCEDURE

Note

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

Tech Tips

  • Read freeze frame data using the Techstream. 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 Techstream, the Data List item "Stop Light Switch" and "ST1" can be read Click here.

PROCEDURE

  1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

    1. Connect the Techstream to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the Techstream on.

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

    5. Read the value displayed on the Techstream.

      OK
      Techstream 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 fully released
    NG

    CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  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 Click here

    OK

  3. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. Inspect the stop light switch assembly Click here.

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  4. CHECK TERMINAL VOLTAGE (STP VOLTAGE)

    1. Disconnect the ECM connector.

      A011U9ZE10

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

      Standard Voltage
      Tester Connection Brake Pedal Operation Specified Condition
      A25-51 (STP) - Body ground Depressed 7.5 to 14 V
      Released Below 1.5 V
      Text in Illustration
      *a Brake Pedal Depressed *b Brake Pedal Released
      *c

      Front view of wire harness connector

      (to ECM)

      		 - -
    NG

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

    OK

    REPLACE ECM Click here