Inspection Procedure 3: The brake warning lamp does not go out (ABS warning lamp is OFF) although the parking brake is released.
| 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 - Troubleshooting
 ).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).
|
OPERATION
- The combination meter illuminates the brake warning lamp when the parking brake is applied.
- When reduction of the brake fluid amount is detected, the brake fluid level switch is turned from "OFF" to "ON". meter-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.
- Parking brake malfunction
- Damaged wiring harness and connectors
- Malfunction of brake fluid level switch
- Combination meter malfunction
|
|
STEP 1. M.U.T.-III CAN bus diagnosis
|
|
|
Use the M.U.T.-III to diagnose the CAN bus lines.
|
|
|
Q.
Is the check result normal?
|
|
|
 Go to Step 2.
|
|
|
|
|
|
 Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
|
|
|
|
|
|
STEP 2. M.U.T.-III diagnosis code for other systems.
|
|
|
Use M.U.T.-III to check that the diagnosis code is set in the combination meter, ETACS-ECU or electric parking brake 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.
|
|
|
|
|
|
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 8.
|
|
|
|
|
|
Replace the brake pad (Refer to GROUP 35A - On-vehicle Service, Brake Pad Replacement ). Then go to Step 8.
|
|
|
|
|
|
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 brake fluid level switch (Refer to GROUP 35A - Master Cylinder Assembly - Disassembly and Reassembly ). Then go to Step 8.
|
|
|
|
|
|
STEP 6. Measure the voltage at the brake fluid level switch connector.
|
|
|
(2)Disconnect the connector and measure at the wiring harness side.
|
|
|
(3)Turn the ignition switch to the "ON" position.
|
|
|
(4)Measure the voltage between the combination meter connector LVL terminal and body earth.
OK: Approximately system voltage
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 7.
|
|
|
|
|
|
The power supply circuit may be open. Repair the wiring harness wires and connectors. Then go to Step 8.
|
|
|
|
|
|
STEP 7. Retest the system
|
|
|
Q.
Does the brake warning lamp turn ON and OFF normally according to the parking brake operation?
|
|
|
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
|
|
|
|
|
|
Replace the combination meter assembly (Refer to GROUP 54A - Combination Meter ).
|
|
|
|
|
|
STEP 8. 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.
|
|
|
|
|
|
Replace the combination meter assembly (Refer to GROUP 54A - Combination Meter ).
|
|
|
|