Inspection Procedure 1: Malfunction of the power supply circuit system of headlamp automatic levelling-ECU
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Whenever the ECU is replaced, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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COMMENTS ON TROUBLE SYMPTOM
If the headlamp automatic levelling system do not work at all, the headlamp automatic levelling-ECU power supply system, earth system, or headlamp automatic levelling-ECU may have a problem.
PROBABLE CAUSES
- Malfunction of the headlamp automatic levelling-ECU
- Damaged harness wires and connectors
DIAGNOSIS PROCEDURE
STEP 1. Resistance measurement at the headlamp automatic levelling-ECU 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 headlamp automatic levelling-ECU connector (GND terminal) and the body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
Go to Step 3.
Go to Step 2.
STEP 2. Check of open circuit in GND line between headlamp automatic levelling-ECU connector and body earth.
Q.
Is the check result normal?
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.
STEP 3. Voltage measurement at the headlamp automatic levelling-ECU connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the ON position.
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(3)Measure the voltage between the headlamp automatic levelling-ECU connector (IG terminal) and the body earth.
OK: System voltage
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Q.
Is the check result normal?
Go to Step 5.
Go to Step 4.
STEP 4. Check of open circuit in IG line between the headlamp automatic levelling-ECU connector and the fusible link.
Q.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
STEP 5. Retest the system.
Check that the headlamp automatic levelling system works normally.
Q.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the headlamp automatic levelling-ECU (Refer to ).