Brake Warning Light Remains ON

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: Brake Warning Light Remains ON

Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter via the CAN and multiplex communication systems.
If any of the following is detected, the brake warning light remains on:

- The skid control ECU connector is disconnected from the skid control ECU.
- The brake fluid level is insufficient.
- The parking brake is applied.
- EBD operation has been disabled.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE:
When replacing the skid control ECU, perform zero point calibration and store system information Vehicle Stability Control System.

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM
(a) Check if a CAN communication system DTC is output Diagnosis System.
Result:






B -- INSPECT CAN COMMUNICATION SYSTEM
A -- Continue to next step.

2. CHECK MULTIPLEX COMMUNICATION SYSTEM
(a) Check if a multiplex communication system DTC is output Reading and Clearing Diagnostic Trouble Codes.
Result:






B -- INSPECT MULTIPLEX COMMUNICATION SYSTEM
A -- Continue to next step.

3. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
(a) Check if the skid control ECU connector is securely connected.
OK:
The connector is securely connected.
NG -- CONNECT CONNECTOR TO ECU CORRECTLY
OK -- Continue to next step.

4. CHECK BATTERY
(a) Check the battery voltage.
Standard voltage:
11 to 14 V
NG -- CHECK OR REPLACE CHARGING SYSTEM OR BATTERY (for 2GR-FSE)
OK -- Continue to next step.

5. INSPECT SKID CONTROL ECU (IG1 TERMINAL)




(a) Disconnect the skid control ECU connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK -- Continue to next step.

6. INSPECT SKID CONTROL ECU (GND1 TERMINAL)




(a) Turn the engine switch off.
(b) Disconnect the skid control ECU connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)
OK -- Continue to next step.

7. READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)
(a) Reconnect the skid control ECU connectors.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG).
(d) Select the Data List mode on the Techstream Data List / Active Test.

ABS / VSC / TRAC





(e) Using the Techstream, check that the switch condition on the Techstream display changes according to parking brake pedal operation.
OK:
The Techstream displays ON or OFF according to parking brake pedal operation.
NG -- INSPECT PARKING BRAKE SWITCH
OK -- Continue to next step.

8. INSPECT BRAKE FLUID LEVEL WARNING SWITCH
(a) Turn the engine switch off.




(b) Remove the reservoir filler cap and strainer.
(c) Disconnect the brake fluid level warning switch connector.
(d) 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:





HINT: If there are no problems after finishing the above check, adjust the brake fluid level to the MAX level.

NG -- REPLACE BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH)
OK -- Continue to next step.

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




(a) Disconnect the combination meter connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

10. INSPECT COMBINATION METER ASSEMBLY
(a) Perform the Active Test of the combination meter (meter CPU) using the Techstream Scan Tool Testing and Procedures.
(b) Check the combination meter.
HINT: Reinstall the connectors and restore the vehicle to its prior condition before checking the combination meter.

OK:
The brake warning light turns on or off in accordance with the Techstream operation.
HINT: If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Problem Symptoms Table.

NG -- REPLACE COMBINATION METER ASSEMBLY
OK -- REPLACE SKID CONTROL ECU
11. INSPECT PARKING BRAKE SWITCH




(a) Turn the engine switch off.
(b) Disconnect the parking brake switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE PARKING BRAKE SWITCH
OK -- Continue to next step.

12. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)
(a) Disconnect the skid control ECU connector.




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





HINT: If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Problem Symptoms Table.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SKID CONTROL ECU