Brake Warning Light Remains ON

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: Brake Warning Light Remains ON

Brake Warning Light Remains ON

DESCRIPTION

The brake warning light comes on when brake fluid is insufficient, the parking brake is applied or the EBD is defective.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
When replacing the master cylinder solenoid, perform zero point calibration Calibration.

PROCEDURE

1. CHECK DTC
(a) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPAIR CIRCUIT INDICATED BY OUTPUT DTC
A -- Continue to next step.
2. INSPECT IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
(a) Check the skid control ECU connector connection.
OK:
The connector is securely connected.
NG -- CONNECT CONNECTOR TO ECU CORRECTLY
OK -- Continue to next step.
3. INSPECT BATTERY
(a) Check the battery voltage.
Standard Voltage:
11 to 14 V
NG -- GO TO CHARGING SYSTEM (ON-VEHICLE INSPECTION)
OK -- Continue to next step.
4. CHECK CAN COMMUNICATION LINE
(a) Turn the engine switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG) and the Techstream on.
(d) Select "CAN Bus Check" from the System Selection Menu screen, and follow the prompts on the screen to inspect the CAN Bus.
OK:
"CAN Bus Check" indicates no malfunctions in CAN communication.
NG -- GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)
OK -- Continue to next step.
5. CHECK DTC (for CAN Communication System)
(a) Turn the engine switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG) and the Techstream on.
(d) Check for DTCs How to Proceed With Troubleshooting.

Result





B -- GO TO CAN COMMUNICATION SYSTEM (DIAGNOSTIC TROUBLE CODE CHART)
A -- Continue to next step.
6. CHECK OPERATION OF BRAKE WARNING LIGHT (ACTIVE TEST)
(a) Turn the engine switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG) and the Techstream on.
(d) Enter the following menus: Body Electrical / Combination Meter / Active Test.
(e) Check the condition of the brake warning light by operating the Techstream.

Combination Meter





OK:
The warning light turns on when operating the Techstream.
NG -- REPLACE COMBINATION METER ASSEMBLY
OK -- Continue to next step.
7. INSPECT SKID CONTROL ECU (IG1 TERMINAL)





(a) Disconnect the A24 skid control ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:






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





(a) Disconnect the A24 and A25 skid control ECU connectors.
(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.
9. INSPECT PARKING BRAKE SWITCH





(a) Disconnect the E53 parking brake switch connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE PARKING BRAKE SWITCH ASSEMBLY
OK -- Continue to next step.
10. 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
OK -- REPLACE MASTER CYLINDER SOLENOID