Brake Warning Light Remains ON [08/2021 -]: Procedure

1. Check that all of the following conditions required for the brake system warning light (red indicator) to turn off are met:
   1. The ABS warning light are not illuminated.

      HINT: 

      If the ABS warning light remains illuminated, make sure that the conditions required for the ABS warning light to turn off are met.

      Refer to ABS Warning Light Remains ON [08/2021 -] 

   2. The brake fluid level in the brake master cylinder reservoir assembly is not low.
   3. Ensure that the brake booster has sufficient vacuum.

      HINT: 

      When the vacuum inside the brake booster decreases, the brake system warning light (red indicator) comes on.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Enter the following menus: Chassis / Brake/EPB / Utility / Vehicle Control History (RoB).
4. Using the Techstream, check for Vehicle Control History (RoB).

   Refer to VEHICLE CONTROL HISTORY (RoB) [08/2021 -]

   Chassis > Brake/EPB > Utility 

   Tester Display
   Vehicle Control History (RoB)

   HINT: 

   If vehicle control history (RoB) is stored when the electronically controlled brake system and electric parking brake system are suspended, the brake system warning light (red indicator) illuminates.

   Result

   Result	Proceed to
   There is no vehicle control history (RoB) for when the electronically controlled brake system and electric parking brake system were suspended.	A
   There is vehicle control history (RoB) for when the electronically controlled brake system and/or electric parking brake system were suspended.	B

Result: 

B 

PERFORM TROUBLESHOOTING AND REPAIR REGARDING VEHICLE CONTROL HISTORY (RoB) 

Refer to VEHICLE CONTROL HISTORY (RoB) [08/2021 -]

Result: 

A 

See step  3

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component without harness connected (Brake Fluid Level Warning Switch (Brake Master Cylinder Reservoir Assembly))

   OK

   The connector is securely connected.

2. Disconnect the A1 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.
3. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   HINT: 

   A float is located inside the reservoir. Its position changes according to the brake fluid level.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1 - 2	Switch off (float up)	1.9 to 2.1 kΩ
   1 - 2	Switch on (float down)	Below 1 Ω

5. If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY. Refer to  DISASSEMBLY [04/2018 -] 

Result: 

OK 

See step  4

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

   OK

   The connector is securely connected.

2. Disconnect the G16 combination meter assembly connector.
3. Disconnect the A1 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G16-12 (SW) - A1-1	Always	Below 1 Ω
   G16-12 (SW) or A1-1 - Body ground	Always	10 kΩ or higher
   A1-2 - Body ground	1 minute or more after disconnecting the cable from the negative (-) battery terminal	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Inspect the vacuum warning switch assembly.

   Refer to ON-VEHICLE INSPECTION [08/2020 -]

   OK

   The vacuum warning switch assembly is normal.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE VACUUM WARNING SWITCH ASSEMBLY. Refer to  REMOVAL [08/2021 -] 

Result: 

OK 

See step  6

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

   OK

   The connector is securely connected.

2. Disconnect the G16 combination meter assembly connector.
3. Disconnect the A2 vacuum warning switch assembly connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G16-7 (VCM) - A2-2	Always	Below 1 Ω
   G16-7 (VCM) or A2-2 - Body ground	Always	10 kΩ or higher
   A2-1 - Body ground	1 minute or more after disconnecting the cable from the negative (-) battery terminal	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Enter the following menus: Body Electrical / Combination Meter / Active Test.
4. Perform the Active Test of the combination meter assembly using the Techstream.

   Refer to DATA LIST / ACTIVE TEST [08/2021 -]

   Body Electrical > Combination Meter > Active Test 

   Tester Display
   Brake Warning

5. Check the combination meter assembly.

   OK

   The brake system warning light (red indicator) turns on or off in accordance with Techstream operation.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [08/2021 -] 

Result: 

NG 

INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -]