Dtc C1426 Stop Light Switch Off Stuck Malfunction


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT OPERATION

READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW/BRAKE PEDAL LOAD SENSING SW)

RECONFIRM DTC

CHECK TERMINAL VOLTAGE AND RESISTANCE (STOP LIGHT SWITCH ASSEMBLY POWER SOURCE TERMINAL)

CHECK TERMINAL VOLTAGE (STP)

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY- BRAKE ACTUATOR ASSEMBLY)

ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION

RECONFIRM DTC

DTC C1426 Stop Light Switch OFF Stuck Malfunction


DESCRIPTION

The skid control ECU (brake actuator assembly) inputs stop light switch signals and brake operation condition.
The skid control ECU (brake actuator assembly) has an open detection circuit, which stores this DTC when detecting an open in the stop light input line or the ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).

DTC Code
DTC Detection Condition
Trouble Area
C1426
When the brake pedal load sensing switch is on, the master cylinder pressure is 2 MPa or higher and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch is off for 2 seconds or more.
  1. STOP fuse
  2. Stop light switch assembly
  3. Stop light switch circuit
  4. Skid control ECU (Brake actuator assembly)
  5. Brake pedal load sensing switch (Brake with switch pedal sub-assembly)

WIRING DIAGRAM

Refer to DTC C1425 (LandCruiser RM000000XIE0VDX_02.html).

INSPECTION PROCEDURE

NOTICE:
  1. When replacing the skid control ECU (brake actuator assembly), perform calibration (LandCruiser RM000000XHR0BJX.html).
  2. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
1.CHECK STOP LIGHT OPERATION

  1. Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

    OK:
    Condition
    		Illumination Condition
    Brake pedal depressed
    		On
    Brake pedal released
    		Off


NG
Go to step 4
OK


2.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW/BRAKE PEDAL LOAD SENSING SW)

  1. Turn the ignition switch off

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light SW
    		Stop light switch/ ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-
    Brake Pedal Load Sensing SW
    		Brake pedal load sensing switch/ ON or OFF
    		ON: Brake pedal depressed beyond specified point
    OFF: Brake pedal not depressed beyond specified point
    		-

  1. Check that the stop light switch display and brake pedal load sensing switch display observed on the intelligent tester change according to the brake pedal operation.

    OK:
    The intelligent tester displays ON or OFF according to brake pedal operation.

  1. Slowly depress the brake pedal and check when the stop light switch and brake pedal load sensing switch are turned on.

    OK:
    The stop light switch turns on first, and then the brake pedal load sensing switch turns on.
    Result
    Result
    		Proceed to
    OK
    		A
    NG (Turning on of stop light switch is not confirmed)
    		B
    NG (Brake pedal load sensing switch turns on first)
    		C


B
Go to step 5

C
Go to step 7
A


3.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Clear the DTCs (LandCruiser RM000000XHV0KDX.html).

  1. Start the engine.

  1. Depress the brake pedal several times to test the stop light circuit.

  1. Check if the same DTC is output (LandCruiser RM000000XHV0KDX.html).

    Result
    Result
    		Proceed to
    DTC C1426 is not output
    		A
    DTC C1426 is output
    		B


B
USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)
A

REPLACE BRAKE ACTUATOR ASSEMBLY (LandCruiser RM0000034UX02TX.html)

4.CHECK TERMINAL VOLTAGE AND RESISTANCE (STOP LIGHT SWITCH ASSEMBLY POWER SOURCE TERMINAL)

  1. Make sure that there is no looseness in the locking part and connecting part of the connectors.

  1. Disconnect the A85 stop light switch assembly connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1426 Stop Light Switch Off Stuck Malfunction

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A85-1(B) - Body ground
    		Always
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Stop Light Switch Assembly)

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A85-3 (GND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK


5.CHECK TERMINAL VOLTAGE (STP)

  1. Make sure that there is no looseness at the locking parts and connecting parts of the connectors.

  1. Disconnect the A6 skid control ECU (brake actuator assembly) connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1426 Stop Light Switch Off Stuck Malfunction

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A6-2 (STP) - Body ground
    		Brake pedal depressed
    		8 to 14 V
    Brake pedal released
    		Below 1.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Skid Control ECU [Brake Actuator Assembly])


NG
Go to step 6
OK

REPLACE BRAKE ACTUATOR ASSEMBLY (LandCruiser RM0000034UX02TX.html)

6.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY- BRAKE ACTUATOR ASSEMBLY)

  1. Disconnect the A85 stop light switch assembly connector.

  1. Disconnect the A6 skid control ECU (brake actuator assembly) connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A85-2 (L) - A6-2 (STP)
    		Always
    		Below 1 Ω
    A85-2 (L) or A6-2 (STP) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE STOP LIGHT SWITCH ASSEMBLY (LandCruiser RM000003QJT01GX.html)

7.ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION

  1. Adjust the brake pedal height and stop light switch assembly installation (LandCruiser RM000002W8X06QX.html).


NEXT


8.RECONFIRM DTC

  1. Clear the DTCs (LandCruiser RM000000XHV0KDX.html).

  1. Start the engine.

  1. Depress the brake pedal several times to test the stop light circuit.

  1. Check if the same DTC is output (LandCruiser RM000000XHV0KDX.html).

    Result
    Result
    		Proceed to
    DTC C1426 is not output
    		A
    DTC C1426 is output
    		B


B
REPLACE BRAKE WITH SWITCH PEDAL SUB-ASSEMBLY (LandCruiser RM000002W9007HX.html)
A

END