Inspection Procedure 1: Check the clearance warning control unit power supply circuit
COMMENTS ON TROUBLE SYMPTOM
If the clearance warning control unit do not work at all, the clearance warning control unit power supply system, earth system, or clearance warning control unit may have a problem.
PROBABLE CAUSES
- Malfunction of clearance warning control unit
- Damaged harness wires and connectors
DIAGNOSIS PROCEDURE
STEP 1. Resistance measurement at the clearance warning control unit connector (EGND terminal).
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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 clearance warning control unit connector (EGND 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 EGND line between clearance warning control unit 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 
).
Repair the connector(s) or wiring harness.
STEP 3. Voltage measurement at the clearance warning control unit connector (IG terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check the voltage between the clearance warning control unit connector (IG terminal) and 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 short to earth, and open circuit in IG line between the ignition switch (IG1) and clearance warning control unit connector.
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
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 clearance warning control unit (Refer to ).