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 and multiplex communications.
If any of the following is detected, the brake warning light remains on:

- The connectors of the skid control ECU and the combination meter are disconnected.
- There is a communication malfunction between the skid control ECU and combination meter.
- When a DTC is stored, there is a malfunction in the skid control ECU internal circuit.
- The brake fluid level is insufficient.
- The parking brake is applied.
- EBD operation is not possible.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
When replacing the brake actuator assembly, perform zero point calibration Calibration.

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM
(a) Check if a CAN communication system DTC is output Reading and Clearing Diagnostic Trouble Codes.
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
OK -- Continue to next step.
5. INSPECT SKID CONTROL ECU (IG1 TERMINAL)




(a) Disconnect the skid control ECU connector.
(b) Turn the ignition switch to the ON position.
(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 (GND TERMINAL)




(a) Turn the ignition 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.
7. 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.
8. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)
OK -- Continue to next step.
9. 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 ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH)
OK -- Continue to next step.
10. 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.
11. INSPECT COMBINATION METER ASSEMBLY
(a) Connect the Techstream to the DLC3.
(b) Perform Active Test of the combination meter (meter CPU) using the Techstream Meter / Gauge System.
OK:
The brake warning light blinks or turns off in accordance with the 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