Inspection Procedure 3: Brake Warning Lamp Stays ON with the Parking Brake Lever Released (ABS warning lamp is OFF).














caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION

  • When the parking brake switch is turned ON, the combination meter terminal No.4 is earthed, and the brake warning lamp illuminates.
  • When reduction of the brake fluid amount is detected, the brake fluid level switch is turned from ON to OFF. ETACS-ECU monitors the brake fluid level switch, and instructs the combination meter via the CAN bus line to illuminate the brake warning lamp.

PROBABLE CAUSES

  • The brake pad thickness is at the limit value or less.
  • The brake fluid amount is at the "LOWER" level or lower.
  • Poor adjustment of the parking brake lever
  • Damaged wiring harness and connectors
  • Parking brake switch malfunction
  • Malfunction of brake fluid level switch
  • Combination meter malfunction
  • Malfunction of ETACS-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ).

STEP 2. M.U.T.-III diagnosis code
Use M.U.T.-III to check that the diagnosis code is set in the combination meter and ETACS-ECU.

Q. Is the diagnosis code set?
Carry out the diagnosis for the diagnosis code.
Go to Step 3.

STEP 3. Brake fluid level check
Check that the brake fluid is filled up to the "MIN" level or higher.

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Brake pad check
Refer to GROUP 35A - On-vehicle Service, Brake Pad Check .

Q. Is the check result normal?
Fill the brake fluid up to the "MAX" level. Then go to Step 17.
Replace the brake pad. <Refer to GROUP 35A - On-vehicle Service, Brake Pad Replacement (except RALLIART), (RALLIART).> Then go to Step 17.

STEP 5. Brake fluid level switch check
Refer to GROUP 35A - On-vehicle Service, Brake Fluid Level Switch Check .

Q. Is the check result normal?
Go to Step 6.
Replace the reservoir tank assembly. <Refer to GROUP 35A - Master Cylinder Assembly · Brake Booster Assembly (except RALLIART), (RALLIART).> Then go to Step 17.

STEP 6. Connector check: A-07 brake fluid level switch connector, C-312 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 7.
Repair the damaged connector.

STEP 7. Measure the voltage at A-07 brake fluid level switch connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between the terminal No. 1 and the body earth.
OK: Approximately battery voltage

Q. Is the check result normal?
Go to Step 9.
Go to Step 8.

STEP 8. Measure the voltage at the C-312 ETACS-ECU connector.
caution With the C-312 ETACS-ECU connector kept connected, disconnect the A-07 brake fluid level switch connector.
(1)Turn the ignition switch to the ON position.
(2)Measure the voltage between terminal No. 1 and the body earth by backprobing.
OK: Approximately battery voltage

Q. Is the check result normal?
Check the wiring harness between the C-312 ETACS-ECU connector terminal No. 1 and the A-07 brake fluid level switch connector terminal No. 1.
Replace the ETACS-ECU. (Refer to GROUP 54A - ETACS .) Then go to Step 17.

STEP 9. Wiring harness check: between A-07 brake fluid level switch connector and body earth
Check for open circuit in the harness wire between A-07 brake fluid level switch connector terminal No. 2 and body earth.

Q. Is the check result normal?
Go to Step 10.
Repair the wiring harness.

STEP 10. Parking brake lever stroke check
Refer to GROUP 36 - On-vehicle Service .

Q. Is the check result normal?
Go to Step 11.
Adjust the parking brake lever stroke. (Refer to GROUP 36 - On-vehicle Service .) Then go to Step 17.

STEP 11. Parking brake switch check
Refer to GROUP 36 - On-vehicle Service .

Q. Is the check result normal?
Go to Step 12.
Replace the parking brake switch. (Refer to GROUP 36 - Parking Brake Lever .) Then go to Step 17.

STEP 12. Connector check: C-116 parking brake switch connector

Q. Is the check result normal?
Go to Step 13.
Repair the damaged connector.

STEP 13. Measure the voltage at C-116 parking brake switch connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between the terminal No. 1 and the body earth.
OK: Approximately battery voltage

Q. Is the check result normal?
Go to Step 16.
Go to Step 14.

STEP 14. Connector check: C-01 combination meter connector, C-16 intermediate connector

Q. Is the check result normal?
Go to Step 15.
Repair the damaged connector.

STEP 15. Voltage measurement with C-01 combination meter connector
(1)Release the parking brake lever (status that the lever is not operated).
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between terminal No. 4 and the body earth by backprobing without disconnecting the connector.
OK: Approximately battery voltage

Q. Is the check result normal?
Repair the wiring harness between the C-01 combination meter connector terminal No. 4 and the C-116 parking brake switch connector terminal No. 1.
Go to Step 16.

STEP 16. Retest the system.

Q. Does the brake warning lamp turn ON and OFF normally according to the parking brake lever operation?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)
Replace the combination meter assembly. (Refer to GROUP 54A - Combination Meter .) Then go to Step 17.

STEP 17. Retest the system.

Q. Does the brake warning lamp turn ON and OFF normally according to the parking brake lever operation?
This diagnosis is complete.
Return to Step 1.