Toyota Tundra Service Manual: Brake Switch "B" Circuit High (P0724)

DESCRIPTION

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

Stop light switch remains ON even when vehicle is driven in GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) 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 GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC. The vehicle must GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) 5 times for 2 driving cycles in order for the DTC to be output.

MONITOR STRATEGY

Related DTCs

P0724: Stop light switch/Range check/Rationality

Required sensors/Components

Stop light switch, Vehicle 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 following DTCs not present

None

Battery voltage

8 V or more

Starter

OFF

Ignition switch

ON

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

Stop light switch

Stuck ON

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
  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:

    • 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.

    Tester 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

    HINT:

    • 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 (19 mph) or more, depress the brake pedal and decelerate the vehicle to 3 km/h (1.8 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 test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • 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 (See page ).

CAUTION / NOTICE / HINT

HINT:

Using the Techstream to read the Data List allows switch, sensor, actuator and other item values to be read without removing any parts. Reading the Data List early in troubleshooting is one way to save time.

NOTICE:

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

  1. Warm up the engine.
  2. Turn the ignition switch off.
  3. Connect the Techstream to the DLC3.
  4. Turn the ignition switch to ON.
  5. Turn the Techstream on.
  6. Enter the following menus: Powertrain / Engine and ECT / Data List.
  7. Follow the instructions on the Techstream and read the Data List.

Item

Measurement Item/

Range (Display)

Normal Condition

Diagnostic Note

Stop Light Switch

Stop light switch status/

ON or OFF

  • Brake pedal is depressed: ON
  • Brake pedal is released: OFF

-

PROCEDURE

1.

INSPECT STOP LIGHT SWITCH

(a) Remove the stop light switch.

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

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

1 - 2

Pin not pushed

Below 1 Ω

Pin pushed

10 kΩ or higher

3 - 4

Pin not pushed

10 kΩ or higher

Pin pushed

Below 1 Ω

NG

REPLACE STOP LIGHT SWITCH

OK

2.

CHECK HARNESS AND CONNECTOR (ECM - BATTERY)

(a) Disconnect the ECM connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A24-36 (STP) - Body ground

Brake pedal is depressed

11 to 14 V

A24-36 (STP) - Body ground

Brake pedal is released

Below 1 V

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    Actuator Supply Voltage Circuit / Open (P0657)

    Camshaft Position Sensor "A" (Bank 1 Sensor 2) (P1340,P1342,P1343)

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