Brake Warning Light Remains ON

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM (for BOSCH Made): Brake Warning Light Remains ON
- Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter assembly 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

HINT
Check the condition of each related circuit connector before troubleshooting Electronic Circuit Inspection Procedure.

PROCEDURE

1. 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.

2. 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.

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 ignition 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 ignition switch off.





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

Standard resistance:





(c) Connect the connector.

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 TO PARKING BRAKE SWITCH)

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





Standard resistance:

Automatic Transaxle
Manual Transaxle










(b) Connect the connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MAIN BODY ECU TO PARKING BRAKE SWITCH)
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 TO 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 (COMBINATION METER TO BRAKE FLUID LEVEL WARNING SWITCH)
OK -- Continue to next step.

10. INSPECT COMBINATION METER ASSEMBLY

(a) Connect the Techstream to the DLC3.

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

ABS / VSC / TRAC





(c) Check BRAKE warning light operation.

OK:

The BRAKE warning light turns on or off in accordance with the Techstream.

NG -- REPLACE COMBINATION METER ASSEMBLY Removal

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal