Inspection Procedure 5: Check the power supply and earth circuit to the
immobilizer-ECU. <Diesel powered vehicle>
COMMENTS ON TROUBLE SYMPTOM
The power supply and earth circuit to
the immobilizer -ECU may be defective.
PROBABLE CAUSES
Damaged harness wires and connectors
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STEP 1. Connector check: D-126 immobilizer-ECU connector
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair
the defective connector.
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STEP 2. Voltage measurement at immobilizer-ECU connector D-126 in order
to check the battery circuit of power supply system to the
immobilizer-ECU.
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(1)Disconnect the immobilizer-ECU connector D-126 and measure
the voltage at immobilizer-ECU connector D-126 harness side.
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(2)Turn the ignition switch to “ON”
position.
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(3)Measure the voltage between terminal 1 and
earth.
OK: System voltage
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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 3.
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STEP 3. Connector check: B-15X engine control relay
connector
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Q.
Is the check result normal?
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Go to Step 4.
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Repair
the defective connector.
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STEP 4. Check the wiring harness between B-15X engine control relay
connector terminal No. 1 and D-126 immobilizer-ECU connector terminal
No.1.
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| note |
Prior to the wiring harness inspection, check joint
connector D-113, intermediate connector D-229, and repair if
necessary.
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- Check the power supply line for open circuit.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair
the wiring harness.
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STEP 5. Resistance measurement at immobilizer-ECU connector D-126 to
check the earth circuit to the immobilizer-ECU connector.
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(1)Disconnect the immobilizer-ECU connector D-126 and measure
the resistance at immobilizer-ECU connector D-126 harness side.
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(2)Turn the ignition switch to “ON”
position.
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(3)Measure the resistance between terminal 2 and
earth.
OK: Continuity exists (2 Ω
or less)
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Q.
Is the check result normal?
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The
procedure is complete.
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Go to Step 6.
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STEP 6. Check the wiring harness between D-126 immobilizer-ECU
connector terminal No.2 and earth.
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- Check the earth wires for open circuit.
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Q.
Is the check result normal?
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The
procedure is complete.
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Repair
the wiring harness.
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