Brake Warning Light Remains ON

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE 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 skid control ECU connector is disconnected from the skid control ECU.
- The brake fluid level is insufficient.
- The parking brake is applied.
- The EBD is defective.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration Programming and Relearning.

PROCEDURE

1. CHECK DTC
(a) Check if the ABS, VSC and/or Electronically Controlled Brake System DTC is output Electronically Controlled Brake System.
Result:






B -- REPAIR CIRCUIT INDICATED BY OUTPUT CODE
A -- Continue to next step.
2. INSPECT CAN COMMUNICATION SYSTEM
(a) Check if the CAN communication system DTC is output Diagnosis System.
Result:






B -- REPAIR CAN COMMUNICATION SYSTEM
A -- Continue to next step.
3. INSPECT MULTIPLEX COMMUNICATION SYSTEM
(a) Check if the multiplex communication system DTC is output Reading and Clearing Diagnostic Trouble Codes.
Result:






B -- REPAIR MULTIPLEX COMMUNICATION SYSTEM
A -- Continue to next step.
4. INSPECT IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
(a) Check the skid control ECU connector's connection.
OK:
The connector is securely connected.
NG -- CONNECT CONNECTOR TO ECU CORRECTLY
OK -- Continue to next step.
5. INSPECT BATTERY
(a) Check the battery voltage.
Voltage:
11 to 14 V
NG -- INSPECT CHARGING SYSTEM
OK -- Continue to next step.
6. 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.
Voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK -- Continue to next step.
7. INSPECT SKID CONTROL ECU (GND TERMINAL)





(a) Disconnect the skid control ECU (A13, A15) connectors.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
8. READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Select the Data List mode on the Techstream.

ABS / VSC / TRAC:





(d) Using the Techstream, check the input of switch operation when the parking brake switch is operated.
OK:
When the parking brake is operated, the display changes as shown above.
NG -- INSPECT PARKING BRAKE SWITCH
OK -- Continue to next step.
9. INSPECT COMBINATION METER ASSEMBLY
(a) Check the combination meter assembly Problem Symptoms Table.
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
10. INSPECT PARKING BRAKE SWITCH





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






NG -- REPLACE PARKING BRAKE SWITCH
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (PARKING BRAKE SWITCH TO COWL SIDE J/B RH ECU)





(a) Disconnect the cowl side J/B RH ECU connector and parking brake switch connector.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO COWL SIDE J/B RH ECU)





(a) Disconnect the skid control ECU connector and cowl side J/B RH ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE COWL SIDE J/B RH ECU