Inspection Procedure A-1: 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
If the ETACS-ECU functions do not work at all, the ETACS-ECU power supply system, earth system, or ETACS-ECU may have a problem.
PROBABLE CAUSES
- Malfunction of the ETACS-ECU
- Damaged harness wires and connectors
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STEP 1. Resistance measurement at ETACS-ECU connector (EARTH, SGND 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 ETACS-ECU connector (EARTH terminal) and body earth.
OK: Continuity exists (2 Ω or less)
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(3)Measure the resistance between the ETACS-ECU connector (SGND terminal) 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 3.
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 Go to Step 2.
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STEP 2. Check of open circuit in EARTH, SGND line between ETACS-ECU connector and body earth
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Q.
Is the check result normal?
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Intermittent malfunction is suspected (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.
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STEP 3. Voltage measurement at ETACS-ECU connector (ETACS +B terminal)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Check the voltage between the ETACS-ECU connector (ETACS +B terminal) and body 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 4.
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STEP 4. Check of short to power supply, short to earth, and open circuit in ETACS +B line between fusible link and ETACS-ECU connector
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Q.
Is the check result normal?
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Intermittent malfunction is suspected (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.
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STEP 5. Retest the system.
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Check that the ETACS-ECU functions work normally.
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Q.
Is the check result satisfactory?
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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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Replace the ETACS-ECU (Refer to ).
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