DTC    P0724    Brake Switch "B" Circuit High

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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.
DTC Detection Condition
Trouble Area
P0724
Stop light switch remains ON even when vehicle repeats 5 cycles of STOP (less than 1.86 mph [3 km/h]) and GO (18.65 mph [30 km/h] or more) (2 trip detection logic):
  1. Short in stop light switch signal circuit
  2. Stop light switch
  3. 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: Stop light switch verify switch input
Required Sensors/Components (Main)
Stop light switch
Required Sensors/Components (Related)
Speed sensor
Frequency of Operation
Continuous
Duration
5 times
MIL Operation
2 driving cycles
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


Monitor runs whenever following DTCs not present
None
Battery voltage
8 V or more
Ignition switch
ON
Starter
Off
GO: Vehicle speed
18.65 mph (30 km/h) or more
STOP: Vehicle speed
Less than 1.86 mph (3 km/h)

TYPICAL MALFUNCTION THRESHOLDS


Brake pedal position switch
On stuck

CONFIRMATION DRIVING PATTERN


A199312E02

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation) (Click here).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the Techstream on [A].
  6. Wait 5 seconds.
  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].
  8. Read the pending DTCs.

    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. 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.

    Techstream Display
    		Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or N/A, perform steps [C] through [E].
  12. Start the engine [C].
  13. Accelerate the vehicle to 19 mph (30 km/h) or more, and then depress the brake pedal and decelerate the vehicle to 1.8 mph (3 km/h) 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 no pending DTC is output, perform a universal trip and check for permanent DTCs (Click here).

    HINT:
    1. If a permanent DTC is output, the system is malfunctioning.
    2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0504 (Click here).

INSPECTION PROCEDURE

HINT:
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 be helpful in determining whether the vehicle was running or stopped, 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.
1.READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. Read the values displayed on the Techstream.


Result:

Item
Measurement Item: Range (display)
Normal Condition
Stop Light Switch
Stop light switch status:
ON or OFF
  1. ON: Brake pedal is depressed
  2. OFF: Brake pedal is released


NG
Go to step 2
OK

CHECK FOR INTERMITTENT PROBLEMS (Click here)  

2.INSPECT STOP LIGHT SWITCH

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



NG
REPLACE STOP LIGHT SWITCH (Click here)
OK


3.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
A252094E02

  1. Disconnect the ECM connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A50-36 (STP) - Body ground
    		Brake pedal released
    		Below 1.5 V
    Brake pedal depressed
    		7.5 to 14 V

  1. Reconnect the ECM connector.



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

REPLACE ECM (Click here)