Inspection Procedure
4: The stop lamps do not illuminate or go out normally.
COMMENTS ON TROUBLE SYMPTOM
If the stop lamps do not illuminate or go out normally, the stop lamp switch input circuit,
earth circuit system, stop lamp switch, stop lamp relay may be defective.
PROBABLE CAUSES
- Malfunction of stop lamp switch
- Malfunction of stop lamp switch input circuit
- Malfunction of stop lamp relay
- Malfunction of rear combination lamp assembly
- Damaged harness wires and connectors
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STEP 1. M.U.T.-III data list.
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Check the ETACS-ECU input signals from the stop lamp switch.
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Item No.
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Item name
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Normal condition
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108
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Stop lamp switch
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OFF to ON (only when switch is operated)
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OK: Normal condition is displayed.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Refer to ETACS-ECU Inspection Procedure 10 "The stop lamp switch signal is not
received."
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STEP 2. Voltage measurement at the stop lamp relay connector (power
supply terminals).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the voltage between the stop lamp relay connector (terminal No.4) and the
body earth.
OK: System voltage
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(4)Measure the voltage between the stop lamp relay connector (terminal No.3) and the
body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 4.
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Go to Step 3.
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STEP 3. Check of short to power supply, and open circuit in power
supply line between the stop lamp relay connector and the fusible link.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 4. Resistance measurement at the high-mounted stop lamp connector,
rear combination lamp (stop: LH) connector or rear combination lamp (stop: RH) connector
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the connector of lamp which does not illuminate
and the body earth.
- Measure the resistance between the high-mounted stop lamp
connector (earth terminal) and the body earth.
- Measure the resistance between the rear combination lamp (stop: LH) connector (earth
terminal) and the body earth.
- Measure the resistance between the rear combination lamp (stop: RH) connector (earth
terminal) and the body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 5.
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STEP 5. Check the following wiring harness.
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Check the wiring harness for earth circuit between the following connectors:
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- Check of open circuit in body earth line between high-mounted stop lamp connector
and body earth.
- Check of open circuit in body earth line between rear combination lamp (stop: LH)
connector and body earth.
- Check of open circuit in body earth line between rear combination lamp (stop: RH)
connector and body earth.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 6. Check the following wiring harness.
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Check the wiring harness for open circuit between the following connectors:
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- Check of open circuit in output line between high-mounted stop lamp connector
and joint connector.
- Check of open circuit in output line between rear combination lamp (stop: LH) connector
and joint connector.
- Check of open circuit in output line between rear combination lamp (stop: RH) connector
and joint connector.
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Q.
Is the check result normal?
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Go to Step 7.
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Replace the connector(s) or wiring harness.
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STEP 7. Voltage measurement at the joint connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Measure the voltage between the joint connector (power supply terminal) and the
body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 9.
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Go to Step 8.
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STEP 8. Check of short to power supply, and open circuit in power
supply line between the joint connector and the fusible link.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 9. Retest the system.
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Check that the stop lamps illuminates normally.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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NO <All the stop lamps do not turn on> : Replace the stop lamp relay. (Refer to GROUP 35A - Brake Pedal  )
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NO <One of the stop lamps does not turn on> : Replace the rear combination lamp assembly or high-mounted stop lamp assembly
having the stop lamp that does not turn on.
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