Inspection Procedure 2: The ignition switch (IG1) signal is not received.
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Whenever the ECU is replaced, ensure that the input signal circuit is normal.
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COMMENTS ON TROUBLE SYMPTOM
If the input signal from the ignition switch (IG1) is defective, the signal is not sent to the communication lines.
PROBABLE CAUSES
- Malfunction of the ETACS-ECU
- Malfunction of the KOS&OSS-ECU <Vehicles with KOS>
- Damaged harness wires and connectors
DIAGNOSIS PROCEDURE
STEP 1. Voltage measurement at ETACS-ECU connector (IG1 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 to the "ON" position.
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(3)Check the voltage between the ETACS-ECU connector (IG1 terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
Go to Step 5.
NO <vehicles without KOS>
: Go to Step 2.
NO <vehicles with KOS> : Go to Step 3.
STEP 2. Check of short to power supply, short to earth, and open circuit in IG1 line between ignition switch (IG1) and ETACS-ECU connector
Q.
Is the check result normal?
Refer to Inspection Procedure "Malfunction of the ignition switch power supply system" 
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Repair the connector(s) or wiring harness.
STEP 3. Check the M.U.T.-III Diagnosis code for other systems
Check that the KOS&OSS-ECU sets a diagnosis code.
Q.
Is the diagnosis code set?
Diagnose the KOS&OSS-ECU. Refer to GROUP 42B, Troubleshooting .
Go to Step 4.
STEP 4. Check of short to power supply, short to earth, and open circuit in IG1 line between IG1 relay connector and ETACS-ECU 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. M.U.T.-III data list
Check the input signal from the ignition switch (IG1).
- Turn the ignition switch to the "ON" position.
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Item No.
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Item name
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Normal condition
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30
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Ignition switch(IG1)
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ON
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OK: Normal condition is displayed.
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 ETACS-ECU (Refer to ).