Inspection Procedure A-1: When the ignition switch is at the LOCK (OFF)
position, the functions do not work normally. Check the battery power supply
circuit to the ETACS-ECU.
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Whenever the ECU is replaced, ensure that the power
supply circuit and the earthing circuit are normal.
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COMMENTS ON TROUBLE SYMPTOM
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If this circuit is defective and the ignition
switch is at the LOCK (OFF) position, the ETACS-ECU does not work. In this
case, the functions below will be suspended.
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- Lamp reminder function
- Keyless entry system
- Ignition key cylinder illumination lamp
- Interior lamps
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However, when the ignition switch is at the ON
position, the functions below will work.
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- Reading diagnosis code and checking input signal by
M.U.T.-III.
- Central door locking
- Headlamp and tail lamp
- Hazard warning lamp
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- Malfunction of the ETACS-ECU
- Damaged harness wires and connectors
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STEP 1. Connector check: D-419 ETACS-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 the D-419 ETACS-ECU
connector.
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(1)Remove the ETACS-ECU, and measure at the junction block
side.
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(2)Voltage between D-419 ETACS-ECU connector terminal No.20
and 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 the wiring harness between D-419 ETACS-ECU connector
terminal No.20 and fusible link (1).
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| note |
Prior to the wiring harness inspection, check
intermediate connector D-241 and junction block connector D-401, 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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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points  ).
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Repair
the wiring harness.
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STEP 4. Resistance measurement at the D-419 ETACS-ECU
connector.
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(1)Remove the ETACS-ECU, and measure at the junction block
side.
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(2)Continuity between D-419 ETACS-ECU connector terminal No.3
and 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 wiring harness between D-419 ETACS-ECU connector
terminal No.3 and body earth.
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| note |
Prior to the wiring harness inspection, check
junction block connector D-405, and repair if necessary.
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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
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points ).
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Repair
the wiring harness.
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STEP 6. Retest the system.
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Check that the battery power supply circuit to
the ETACS-ECU is normal.
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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 ).
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Replace the ETACS-ECU.
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