Inspection Procedure
2: Communication with the ETACS-ECU is not Possible.
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Whenever the ECU is replaced,
ensure that the power supply circuit, the earthing circuit and the communication circuit are
normal.
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COMMENTS ON TROUBLE SYMPTOM
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It is suspected that the power supply circuit to the ETACS-ECU is defective, or the wiring
harness between the SWS monitor and the ETACS-ECU or their connector(s) is damaged. If the battery
power supply circuit to the ECU (terminal No.20 of the ETACS-ECU) is damaged, also check the
power supply circuit from the ignition switch (IG1) (terminal No.8 of the ETACS-ECU), and repair
if necessary. If the earth circuit to the ECU (terminal No.3 of the ETACS-ECU) is defective,
also check the earth circuit to the sensor (terminal No.56 of the ETACS-ECU), and repair if
necessary.
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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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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. 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)Turn the ignition switch to the ON position.
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(3)Voltage between D-419 ETACS-ECU connector terminal No.8 and body earth
OK: System voltage
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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.8 and the ignition switch (IG1).
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Prior to the wiring harness inspection, check junction block connector D-403, 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 6. 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)Resistance between D-419 ETACS-ECU connector terminal No.3, 56 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 8.
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Go to Step 7.
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STEP 7. Check the wiring harness between D-419 ETACS-ECU connector
terminal No.3, 56 to body earth.
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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 8. Connector check: D-420 ETACS-ECU connector and D-311 column
switch connector
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Q.
Is the check result normal?
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Go to Step 9.
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Repair the defective connector.
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STEP 9. Check the wiring harness from D-420 ETACS-ECU connector terminal
Nos.59 and 68 to D-311 column switch connector terminal Nos.3 and 2.
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- Check the communication lines for open circuit.
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Q.
Is the check result normal?
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Go to Step 10.
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Repair the wiring harness.
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STEP 10. ECU check by using the SWS monitor
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OK: "OK" is displayed on the "ETACS ECU" menu.
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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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