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 CAN communication.
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 is not possible.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE:
When replacing the brake actuator assembly, perform zero point calibration Programming and Relearning.

PROCEDURE

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






B -- INSPECT CAN COMMUNICATION SYSTEM
A -- Continue to next step.
2. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
(a) Check if the skid control ECU connector is securely connected.
OK:
The connector should be securely connected.
NG -- CONNECT CONNECTOR TO ECU CORRECTLY
OK -- Continue to next step.
3. CHECK BATTERY
(a) Check the battery voltage.
Standard voltage:
11 to 14 V
NG -- CHECK AND REPLACE CHARGING SYSTEM OR BATTERY
OK -- Continue to next step.
4. 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.
5. INSPECT SKID CONTROL ECU (GND TERMINAL)




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
6. INSPECT PARKING BRAKE SWITCH




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






NG -- REPLACE PARKING BRAKE SWITCH
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - PARKING BRAKE SWITCH)




(a) Disconnect the main body ECU 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.
8. INSPECT BRAKE FLUID LEVEL WARNING SWITCH




(a) Remove the reservoir tank cap and strainer.
(b) Disconnect the brake fluid level warning switch connector.
(c) 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 is no problem 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 Active Test of the combination meter (meter CPU) using Techstream Scan Tool Testing and Procedures.
OK:
The BRAKE warning light turns on or off in accordance with Techstream.
HINT:
- Reinstall the connectors and restore the vehicle to its prior condition before checking the combination meter.
- 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 BRAKE ACTUATOR ASSEMBLY