Brake Warning Light Remains ON

BRAKE CONTROL: ANTI-LOCK BRAKE SYSTEM: Brake Warning Light Remains ON

Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU sends the indicator signals to the combination meter assembly via the CAN communication system.
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 DTC
(a) Check if an ABS DTC is output ABS (Antilock Brake System).
Result:






B -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
A -- Continue to next step.
2. INSPECT CAN COMMUNICATION SYSTEM
(a) Check if a CAN communication system DTC is output ABS (Antilock Brake System).
Result:






B -- REPAIR CAN COMMUNICATION SYSTEM
A -- Continue to next step.
3. CHECK IF SKID CONTROL ECU CONNECTOR SECURELY CONNECTED
(a) Check if the skid control ECU connector is connected securely.
OK:
The connector should be 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 -- INSPECT CHARGING SYSTEM
OK -- Continue to next step.
5. INSPECT SKID CONTROL ECU CONNECTOR (IG1 TERMINAL VOLTAGE)




(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.
6. INSPECT SKID CONTROL ECU CONNECTOR (GND TERMINAL CONTINUITY)




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

Automatic Transaxle





Manual Transaxle





NG -- REPLACE PARKING BRAKE SWITCH
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU TO 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:
Automatic Transaxle






Manual Transaxle






(c) Connect the connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MAIN BODY ECU TO PARKING BRAKE SWITCH)
OK -- Continue to next step.
9. INSPECT BRAKE FLUID LEVEL WARNING SWITCH ASSEMBLY




(a) Remove the reservoir tank cap.
(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.
10. CHECK HARNESS AND CONNECTOR (BRAKE FLUID LEVEL WARNING SWITCH TO COMBINATION METER)




(a) Disconnect the combination meter assembly connector.
(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 (BRAKE FLUID LEVEL WARNING SWITCH TO COMBINATION METER)
OK -- Continue to next step.
11. INSPECT COMBINATION METER ASSEMBLY
(a) Connect Techstream to the DLC3.
(b) Select the "Active Test" on Techstream Data List / Active Test.

Active Test: ABS / VSC / TRAC





(c) Check the ABS warning light operation.
OK:
The BRAKE warning light turns on or off in accordance with Techstream.
Result:






C -- REPLACE COMBINATION METER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- REPLACE BRAKE ACTUATOR ASSEMBLY