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 - CAN Bus Diagnostics Table
 ).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASTC-ECU) is replaced, always carry out
the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to ).
|
OPERATION
- When the parking brake switch is turned "ON", the combination meter (BRK
terminal) 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 "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.
- 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
|
|
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 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.
|
|
|
|
|
|
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 11.
|
|
|
|
|
|
Replace the brake pad. (Refer to GROUP 35A - On-vehicle Service, Brake
Pad Replacement .) Then go to Step 11.
|
|
|
|
|
|
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 11.
|
|
|
|
|
|
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 9.
|
|
|
|
|
|
STEP 7. Parking brake lever stroke check
|
|
|
Refer to GROUP 36 - On-vehicle Service .
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 8.
|
|
|
|
|
|
Adjust the parking brake lever stroke. (Refer to GROUP 36 - On-vehicle
Service .) Then go to Step 11.
|
|
|
|
|
|
STEP 8. Parking brake switch check
|
|
|
Refer to GROUP 36 - On-vehicle Service .
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 9.
|
|
|
|
|
|
Replace the parking brake switch (Refer to GROUP 36 - Parking Brake Lever .)
Then go to Step 11.
|
|
|
|
|
|
STEP 9. Measure the voltage at the parking brake 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 BRK terminal and body
earth.
OK: Approximately system voltage
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 10.
|
|
|
|
|
|
The power supply circuit may be open. Repair the wiring harness wires and connectors.
Then go to Step 10.
|
|
|
|
|
|
STEP 10. Retest the system
|
|
|
Q.
Does the brake warning lamp turn ON and OFF normally according to the parking brake
lever 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 .) Then go to Step 11.
|
|
|
|
|
|
STEP 11. 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.
|
|
|
|