Inspection Procedure
2: When the ignition switch is turned to the "ON" position (engine not
running), Brake warning
lamp does not illuminate.
OPERATION
By turning the warning lamp drive transistor inside the
ABS-ECU (ON → OFF), the
ABS-ECU illuminates the brake warning lamp. Then, if the system has no
abnormality, the ABS-ECU
turns off the warning lamp by turning the warning lamp drive transistor (OFF
→ ON).
COMMENT ON TROUBLE SYMPTOM
The cause that the brake warning lamp
does not illuminate may be the open or short circuit
in the power supply line to the brake warning lamp, combination meter
malfunction, short circuit
in the lamp drive signal line to the earth side, open circuit in the brake
warning lamp earth
line, or the ABS-ECU internal circuit failure.
PROBABLE CAUSES
The most likely causes for this case
are:
- Blown fuse
- Damaged wiring harness or connector
- Combination meter defect
- Malfunction of the ABS-ECU
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STEP 1. Voltage measurement at combination meter connector
D-02.
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Prior to the voltage with the D-02 combination
meter connector, check the D-02 combination
meter connector, and repair if necessary.
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(1)Do not disconnect combination meter connector D-02, and
check at the harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Measure the voltage between terminal 45 and
earth.
OK: System voltage
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Q.
Is the check result normal?
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 Go to Step 2.
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 Replace the combination meter.
Then go to Step 3.
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STEP 2. Check the harness wire between the combination meter connector
D-02 terminal No.45 and ABS-ECU connector D-250 terminal
No.39.
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Prior to the wiring harness inspection, check
intermediate connector D-230, and repair
if necessary.
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Q.
Is the check result normal?
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Repair the ABS-ECU. Then go to
Step 3.
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Repair
the harness wire.
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STEP 3. Retest the system.
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Q.
Does the brake warning lamp illuminate for 3 seconds when the ignition
switch is turned
to the "ON" position with engine stopped or upon start-up?
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Intermittent malfunction (Refer to
GROUP 00, How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction  ).
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Start over at Step 1.
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