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Home >> Mitsubishi >> 2012 >> Lancer AWD L4-2.0L Turbo (4B11T) >> Repair and Diagnosis >> Brakes and Traction Control >> Antilock Brakes / Traction Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Active Stability Control System (ASC) >> Inspection Procedure 3

Inspection Procedure 3




Inspection Procedure 3: Brake warning light stays ON with the parking brake lever released.





















CAUTION:

- If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines CAN Bus Line Diagnostics Flow).

- Whenever ECU is replaced, ensure that the CAN bus lines are normal.

CIRCUIT OPERATION

- When the parking brake switch is turned ON, the combination meter terminal No.4 is grounded, and then the brake warning light 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 light.

COMMENTS ON TROUBLE SYMPTOM

This may be caused by the ground fault in the parking brake switch circuit and the open circuit in the brake fluid level switch circuit.

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

- Brake fluid level switch malfunction

- Combination meter malfunction

- Malfunction of ETACS-ECU

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)

- MB991827: M.U.T.-III USB Cable

- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.

Use scan tool to diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 2.
NO Repair the CAN bus lines CAN Bus Line Diagnostics Flow).
On completion, go to Step 2.
STEP 2. DTC check after resetting CAN bus lines

Use scan tool to check that the DTC is set in the combination meter and ETACS-ECU.

Q. Is any DTC set?

YES Carry out the diagnosis for the DTC.
NO 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?

YES Go to Step 5.
NO Go to Step 4.
STEP 4. Brake pad check

Brake Pad Check.

Q. Is the check result normal?

YES Fill the brake fluid up to the "MAX" level. Then go to Step 18.
NO Replace the brake pad Brake Pad Replacement[Except Ralliart] [Except RALLIART], Brake Pad Replacement[Ralliart] [RALLIART]).
Then go to Step 18.
STEP 5. Brake fluid level switch check

Testing and Inspection.

Q. Is the check result normal?

YES Go to Step 6.
NO Replace the reservoir tank assembly Master Cylinder Assembly and Brake Booster Assembly Removal and Installation [Except Ralliart] [Except RALLIART], Master Cylinder Assembly and Brake Booster Assembly Removal and Installation [Ralliart] [RALLIART]). Then go to Step 18.
STEP 6. Connector check: A-06 brake fluid level switch connector, C-312 ETACS-ECU connector

Q. Is the check result normal?

YES Go to Step 7.
NO Repair the damaged connector.
STEP 7. Measure the voltage at A-06 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 ground.
OK: Approximately system voltage

Q. Is the check result normal?

YES Go to Step 10.
NO 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-06 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 ground by backprobing.
OK: Approximately system voltage

Q. Is the check result normal?

YES Go to Step 9.
NO Replace the ETACS-ECU Electronic Time and Alarm Control System (ETACS)-ECU Removal and Installation).
Then go to Step 18.
STEP 9. Wiring harness check: between A-06 brake fluid level switch connector and C-312 ETACS-ECU connector

Check for open circuit in the harness wire between A-06 brake fluid level switch connector terminal No.1 and C-312 ETACS-ECU connector terminal No.1.

Q. Is the check result normal?

YES Go to Step 16.
NO Repair the wiring harness. Then go to Step 18.
STEP 10. Wiring harness check: between A-06 brake fluid level switch connector and body ground

Check for open circuit in the harness wire between A-06 brake fluid level switch connector terminal No.2 and body ground.

Q. Is the check result normal?

YES Go to Step 11.
NO Repair the wiring harness.
STEP 11. Parking brake lever stroke check

Procedures.

Q. Is the check result normal?

YES Go to Step 12.
NO Adjust the parking brake lever stroke Procedures).
Then go to Step 18.
STEP 12. Parking brake switch check

Testing and Inspection.

Q. Is the check result normal?

YES Go to Step 13.
NO Replace the parking brake switch Removal and Replacement).
Then go to Step 18.
STEP 13. Connector check: C-117 parking brake switch connector

Q. Is the check result normal?

YES Go to Step 14.
NO Repair the damaged connector.
STEP 14. Measure the voltage at C-117 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 ground.
OK: Approximately system voltage

Q. Is the check result normal?

YES Go to Step 17.
NO Go to Step 15.
STEP 15. Connector check: C-04 Combination meter connector, C-22 intermediate connector

Q. Is the check result normal?

YES Go to Step 16.
NO Repair the defective connector.
STEP 16. Wiring harness check: between the C-04 combination meter connector and the C-117 parking brake switch connector

Check for short circuit in the harness wire between the C-04 combination meter connector terminal No.4 and the C-117 parking brake switch connector terminal No.1.

Q. Is the check result normal?

YES Go to Step 17.
NO Repair the wiring harness. Then go to Step 18.
STEP 17. Retest the system.

Q. Does the brake warning light turn ON and OFF normally according to the parking brake lever operation?

YES Intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the combination meter assembly Removal and Replacement). Then go to Step 18.
STEP 18. Retest the system.

Q. Does the brake warning light turn ON and OFF normally according to the parking brake lever operation?

YES The procedure is complete.
NO Return to Step 1.
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