Brake Warning Light Remains On

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: 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 communication.

If any of the following is detected, the brake warning light / red (malfunction) 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

NOTICE:
When replacing the brake booster with master cylinder (skid control ECU), perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. CHECK DTC

(a) Check if a ABS, VSC and/or electronically controlled brake system DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Electronically Controlled Brake System
A -- Continue to next step.

2. CHECK CAN COMMUNICATION SYSTEM

(a) Check if a CAN communication system DTC is output Diagnosis System.

Result:





B -- INSPECT CAN COMMUNICATION SYSTEM How to Proceed With Troubleshooting
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 AUXILIARY BATTERY

(a) Check the auxiliary battery voltage.

Standard Voltage:

11 to 14 V

NG -- CHARGE OR REPLACE AUXILIARY BATTERY
OK -- Continue to next step.

5. INSPECT SKID CONTROL ECU (IG1 TERMINAL)

(a) Disconnect the skid control ECU connector.





(b) Turn the power switch on (IG).

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





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

6. INSPECT SKID CONTROL ECU (GND TERMINAL)

(a) Turn the power switch off.





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

Standard Resistance:





Text in Illustration





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

7. READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)

(a) Reconnect the skid control ECU connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(e) Using the Techstream, check if the switch condition on the Techstream changes according to parking brake operation.

OK:

The Techstream displays ON or OFF according to parking brake operation.

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

8. INSPECT COMBINATION METER

(a) Turn the power switch off.

(b) Perform the Active Test of the combination meter (meter CPU) using the Techstream Scan Tool Testing and Procedures.

(c) Check the combination meter.

OK:

The brake warning light / red (malfunction) turns on or off in accordance with the Techstream operation.

HINT
If troubleshooting has been carried out according to 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 Removal

OK -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

9. INSPECT PARKING BRAKE SWITCH

(a) Turn the power switch off.





(b) Disconnect the parking brake switch connector.

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

Standard Resistance:





Text in Illustration





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

10. 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:





HINT
If troubleshooting has been carried out according to 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 MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK) Removal