Anti-Lock Brake System Brake Warning Light Remains On


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM

CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

CHECK TERMINAL VOLTAGE (IG1)

CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

READ VALUE USING INTELLIGENT TESTER (PARKING BRAKE SW)

INSPECT BRAKE FLUID LEVEL WARNING SWITCH

CHECK HARNESS AND CONNECTOR (COMBINATION METER - BRAKE FLUID LEVEL WARNING SWITCH)

READ VALUE USING INTELLIGENT TESTER (BRAKE WARNING LIGHT)

INSPECT PARKING BRAKE SWITCH

CHECK HARNESS AND CONNECTOR (PARKING BRAKE SWITCH - MAIN BODY ECU )

ANTI-LOCK BRAKE SYSTEM - Brake Warning Light Remains ON


DESCRIPTION

The skid control ECU is connected to the combination meter via CAN communication.
If any of the following is detected, the brake warning light remains on:
  1. The skid control ECU connector is disconnected from the skid control ECU.
  2. The brake fluid level is insufficient.
  3. The parking brake is applied.
  4. EBD operation is not possible.
  5. The voltage at terminal IG1 is high.

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System.Anti-Lock Brake System Brake Warning Light Remains On


INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform calibration (LandCruiser RM000000XHR0BJX.html).
1.CHECK CAN COMMUNICATION SYSTEM

  1. Check if CAN communication system DTCs are output (for LHD without Entry and Start System: LandCruiser RM000000WIB0EDX.html, for RHD without Entry and Start System: LandCruiser RM000000WIB0EFX.html).

    Result
    Result
    		Proceed to
    DTC not output
    		A
    DTC output
    		for LHD without Entry and Start System
    		B
    DTC output
    		for RHD without Entry and Start System
    		C


B
GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (LandCruiser RM000001RSO0BYX.html)

C
GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (LandCruiser RM000001RSO0C0X.html)
A


2.CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

  1. Check if the skid control ECU connector is securely connected.

    OK:
    The connector is securely connected.


NG
CONNECT CONNECTOR TO ECU CORRECTLY
OK


3.CHECK TERMINAL VOLTAGE (IG1)

  1. Disconnect the A6 skid control ECU connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System.Anti-Lock Brake System Brake Warning Light Remains On

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A6-34 (IG1) - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Skid Control ECU)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK


4.CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

  1. Disconnect the A6 skid control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A6-1 (GND1) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)
OK


5.READ VALUE USING INTELLIGENT TESTER (PARKING BRAKE 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
    Parking Brake SW
    		Parking brake switch/ ON or OFF
    		ON: Parking brake applied
    OFF: Parking brake released
    		-

  1. Using the intelligent tester, check the input of the switch operation when the parking brake pedal is operated.

    OK:
    When the parking brake is operated, the display changes as shown above.


NG
Go to step 9
OK


6.INSPECT BRAKE FLUID LEVEL WARNING SWITCH

  1. Turn the ignition switch off.

  1. Remove the reservoir filler cap and strainer.

  1. Disconnect the A44 brake fluid level warning switch connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System.Anti-Lock Brake System Brake Warning Light Remains On

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

    HINT:
    A float is located inside the reservoir. Its position can be changed by increasing or decreasing the level of brake fluid.
    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Switch off (Float up)
    		10 kΩ or higher
    Switch on (Float down)
    		Below 1 Ω
    Text in Illustration
    *a
    		Component without harness connected
    (Brake Fluid Level Warning Switch)
    HINT:
    If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.


NG
REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY (LandCruiser RM000002WF2056X.html)
OK


7.CHECK HARNESS AND CONNECTOR (COMBINATION METER - BRAKE FLUID LEVEL WARNING SWITCH)

  1. Disconnect the G6 combination meter connector.

  1. Disconnect the A44 brake fluid level warning switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    G6-31 (SW) - A44-1
    		Always
    		Below 1 Ω
    G6-31 (SW) - Body ground
    		Always
    		10 kΩ or higher
    A44-2 - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8.READ VALUE USING INTELLIGENT TESTER (BRAKE WARNING LIGHT)

  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
    Brake Warning Light
    		Brake warning light/ ON or OFF
    		OFF
    		-

  1. When performing the Brake Warning Light Active Test, check Brake Warning Light in the Data List (LandCruiser RM000000XHW0GJX.html).

    ABS/VSC/TRC
    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Brake Warning Light
    		Brake warning light
    		Warning light ON/OFF
    		Observe combination meter

    Result
    Result
    		Proceed to
    Data List Display
    		Data List Display when Performing Active Test ON/OFF Operation
    ON
    		Does not change between ON and OFF
    		A
    Changes between ON and OFF
    		B
    OFF
    		Does not change between ON and OFF
    		A
    Changes between ON and OFF
    		B


B
GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (LandCruiser RM000002Z4L055X.html)
A

REPLACE BRAKE ACTUATOR ASSEMBLY (LandCruiser RM0000034UX02TX.html)

9.INSPECT PARKING BRAKE SWITCH

  1. Turn the ignition switch off.

  1. Disconnect the G77 parking brake switch connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System.Anti-Lock Brake System Brake Warning Light Remains On

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - Body ground
    		Parking brake switch on
    (Switch pin free)
    		Below 1 Ω
    Parking brake switch off
    (Switch pin pushed in)
    		10 kΩ or higher
    Text in Illustration
    *a
    		Component without harness connected
    (Parking Brake Switch)


NG
REPLACE PARKING BRAKE SWITCH (LandCruiser RM000003D75013X.html)
OK


10.CHECK HARNESS AND CONNECTOR (PARKING BRAKE SWITCH - MAIN BODY ECU )

  1. Remove the main body ECU (LandCruiser RM000003WBO05FX.html).

  1. Disconnect the G77 parking brake switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A-12 (PKB) - G77-1
    		Always
    		Below 1 Ω
    A-12 (PKB) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)