Anti-Lock Brake System (For Sedan) Brake Warning Light Remains On

Brake. Yaris. Ncp93, 131
Brake Control Dynamic Control Systems. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

PREPARE FOR INSPECTION

CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

CHECK CAN COMMUNICATION SYSTEM

PERFORM ACTIVE TEST USING TECHSTREAM (Indicat. Lamp Brake)

READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)

INSPECT BRAKE FLUID LEVEL WARNING SWITCH

CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)

CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

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

INSPECT PARKING BRAKE SWITCH ASSEMBLY

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

ANTI-LOCK BRAKE SYSTEM (for Sedan) - 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.

WIRING DIAGRAM


Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan).Anti-Lock Brake System (For Sedan) Brake Warning Light Remains On


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
1.PREPARE FOR INSPECTION

  1. Check that both of the following conditions are satisfied.

    1. The brake fluid level in the brake master cylinder reservoir is correct.
    2. The parking brake is released.
    HINT:
    When the ABS warning light remains illuminated, repair the malfunction in the ABS system first.

NEXT


2.CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

  1. Check if the brake actuator assembly (skid control ECU) connector is securely connected.

    OK:
    The connector is securely connected.


NG
CONNECT CONNECTOR TO ECU CORRECTLY
OK


3.CHECK CAN COMMUNICATION SYSTEM

  1. Check if CAN communication system DTCs are output (YARIS_NCP93 RM000001D3E00OX.html).

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


B
GO TO CAN COMMUNICATION SYSTEM (YARIS_NCP93 RM000001D3500JX.html)
A


4.PERFORM ACTIVE TEST USING TECHSTREAM (Indicat. Lamp Brake)

  1. Turn the ignition switch off.

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Enter the following menus: Body Electrical / Combination Meter / Active Test.

  1. According to the display on the Techstream, perform the Active Test.

    Combination Meter
    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Indicat. Lamp Brake
    		Brake warning light
    		OFF/ON
    		Perform the test with the vehicle stopped and the engine idling

  1. Check that the brake warning light on the combination meter turns on or off in accordance with the tester operation.

    OK:
    The brake warning light turns on or off in accordance with the tester operation.


NG
GO TO METER / GAUGE SYSTEM (YARIS_NCP93 RM000001DAG00QX.html)
OK


5.READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)

  1. Turn the ignition switch off.

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. According to the display on the Techstream, read the Data List.

    ABS/VSC/TRAC
    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 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 10
OK


6.INSPECT BRAKE FLUID LEVEL WARNING SWITCH


    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan).Anti-Lock Brake System (For Sedan) Brake Warning Light Remains On

  1. Turn the ignition switch off.

  1. Remove the reservoir filler cap and strainer.

  1. Disconnect the brake fluid level warning switch connector.

  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
    1 - 2
    		Switch ON (Float down)
    		Below 1 Ω
    HINT:
    If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.
Text in Illustration
*a
Component without harness connected
(Brake Fluid Level Warning Switch)

  1. Reconnect the brake fluid level warning switch connector.

  1. Reinstall the reservoir filler cap and strainer.



NG
REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH) (YARIS_NCP93 RM000001K68014X.html)
OK


7.CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)

  1. Turn the ignition switch off.

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

  1. Disconnect the A15 brake actuator assembly (skid control ECU) connector.

  1. Check the connector case and terminals for deformation and corrosion.

    OK:
    No deformation or corrosion.


    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan).Anti-Lock Brake System (For Sedan) 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
    A15-34 (IG1) - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Brake Actuator Assembly (Skid Control ECU))


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


8.CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

  1. Turn the ignition switch off.



    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan).Anti-Lock Brake System (For Sedan) Brake Warning Light Remains On

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A15-1 (GND1) - Body ground
    		Always
    		Below 1 Ω
    A15-13 (GND2) - Body ground
    		Always
    		Below 1 Ω
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Brake Actuator Assembly (Skid Control ECU))

  1. Reconnect the A15 brake actuator assembly (skid control ECU) connector.



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


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

  1. Disconnect the D76 combination meter assembly connector and the A10 brake fluid level warning switch.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D76-2 (SW) - A10-1 (+)
    		Always
    		Below 1 Ω
    A10-2 (E) - Body ground
    		Always
    		Below 1 Ω
    D76-2 (SW) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the D76 combination meter assembly connector and the A10 brake fluid level warning switch.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE BRAKE ACTUATOR (YARIS_NCP93 RM000001BXP02FX.html)

10.INSPECT PARKING BRAKE SWITCH ASSEMBLY

  1. Disconnect the D21 parking brake switch assembly connector.



    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan).Anti-Lock Brake System (For Sedan) Brake Warning Light Remains On

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - Body ground
    		Parking brake applied
    (Switch pin not pushed in)
    		Below 1 Ω
    Parking brake released
    (Switch pin pushed in)
    		10 kΩ or higher
    Text in Illustration
    *a
    		Component without harness connected
    (Parking Brake Switch Assembly)

  1. Reconnect the D21 parking brake switch assembly connector.



NG
REPLACE PARKING BRAKE SWITCH ASSEMBLY (YARIS_NCP93 RM000001C4X01EX.html)
OK


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

  1. Disconnect the 4C main body ECU connector and the D21 parking brake switch assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    4C-2 - D21-1
    		Always
    		Below 1 Ω
    4C-2 - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the 4C main body ECU connector and the D21 parking brake switch assembly connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MAIN BODY ECU