Inspection Procedure
2: Brake warning lamp stays ON with the parking brake lever released (ABS warning lamp is OFF).
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- If
there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior
to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics
Table
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- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out
the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to and ).
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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
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STEP 1. M.U.T.-III CAN bus diagnosis
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
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STEP 2. M.U.T.-III diagnosis code for other systems.
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Use M.U.T.-III to check that the diagnosis code is stored in the combination meter and
ETACS-ECU.
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Q.
Is the diagnosis code stored?
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Carry out the diagnosis for the diagnosis code. Then go to Step 11.
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Go to Step 3.
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STEP 3. Brake fluid level check
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Check that the brake fluid is filled up to the "MIN" level or higher.
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Q.
Is the check result normal?
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Go to Step 5.
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Go to Step 4.
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Refer to GROUP 35A - On-vehicle Service, Brake Pad Check .
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Q.
Is the check result normal?
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Fill the brake fluid up to the "MAX" level. Then go to Step 11.
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Replace the brake pad (Refer to GROUP 35A - On-vehicle Service, Brake
Pad Replacement ). Then go to Step 11.
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STEP 5. Brake fluid level switch check
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Refer to GROUP 35A - On-vehicle Service, Brake Fluid Level Sensor Check .
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Q.
Is the check result normal?
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Go to Step 6.
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Replace the reservoir tank assembly (Refer to GROUP 35A - Master Cylinder
Assembly and Brake Booster Assembly <LHD>, <RHD>). Then
go to Step 11.
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STEP 6. Measure the voltage at the brake fluid level switch connector.
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(2)Disconnect the connector and measure at the wiring harness side.
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(3)Turn the ignition switch to the "ON" position.
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(4)Measure the voltage between the combination meter connector LVL terminal and body
earth.
OK: Approx. system voltage
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Q.
Is the check result normal?
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Go to Step 7.
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The power supply circuit may be open. Repair the wiring harness wires and connectors.
Then go to Step 11.
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STEP 7. Parking brake lever stroke check
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Refer to GROUP 36 - On-vehicle Service .
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Q.
Is the check result normal?
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Go to Step 8.
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Adjust the parking brake lever stroke (Refer to GROUP 36 - On-vehicle
Service ). Then go to Step 11.
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STEP 8. Parking brake switch check
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Refer to GROUP 36 - On-vehicle Service .
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Q.
Is the check result normal?
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Go to Step 9.
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Replace the parking brake switch (Refer to GROUP 36 - Parking Brake Lever ).
Then go to Step 11.
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STEP 9. Measure the voltage at the parking brake switch connector.
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(2)Disconnect the connector and measure at the wiring harness side.
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(3)Turn the ignition switch to the "ON" position.
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(4)Measure the voltage between the combination meter connector BRK terminal and body
earth.
OK: Approx. system voltage
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Q.
Is the check result normal?
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Go to Step 10.
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The power supply circuit may be open. Repair the wiring harness wires and connectors.
Then go to Step 11.
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STEP 10. Retest the system
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Q.
Does the brake warning lamp turn ON and OFF normally according to the parking brake
lever operation?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction ).
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Replace the combination meter assembly (Refer to GROUP 54A - Combination
Meter ). Then go to Step 11.
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STEP 11. Retest the system
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Q.
Does the brake warning lamp turn ON and OFF normally according to the parking brake
lever operation?
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This diagnosis is complete.
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Return to Step 1.
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