Inspection Procedure 11: Check the CAN box unit power supply circuit.
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Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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TECHNICAL DESCRIPTION (COMMENT)
If the CAN box unit functions do not work at all, the CAN box unit power supply system, body earth system, or CAN box unit may have a problem.
PROBABLE CAUSES
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The CAN box unit may be defective
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STEP 1. Connector check: C-15 CAN box unit connector
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair or replace the damaged component(s).
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STEP 2. Resistance measurement at C-15 CAN box unit connector.
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(1)Disconnect C-15 CAN box unit connector and measure the resistance available at the wiring harness side of the connector.
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(2)Check the continuity between C-15 CAN box unit connector terminal No.1 and body earth.
OK: Continuity exists (2 ohms or less)
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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 C-15 CAN box unit connector terminal No.1 and the body earth.
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Q.
Is the check result normal?
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No action is necessary and testing is complete.
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Repair the wiring harness.
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STEP 4. Voltage measurement at C-15 CAN box unit connector
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(1)Disconnect CAN box unit connectors C-15 measure the voltage available at the wiring harness side of the connector.
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(2)Measure the voltage between C-15 CAN box unit connector terminal No.2 and body earth.
OK: Battery positive 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 C-15 CAN box unit connector terminal No.2 and fusible link (34).
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Prior to the wiring harness inspection, check intermediate connector C-19 and ETACS-ECU connectors C-307 and C-317, and repair if necessary.
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Q.
Is the check result normal?
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No action is necessary and testing is complete.
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Repair the wiring harness.
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STEP 6. Check the wiring harness between C-15 CAN box unit connector terminal No.10 and fusible link (38).
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Prior to the wiring harness inspection, check intermediate connector C-19 and ETACS-ECU connectors C-309 and C-315, and repair if necessary.
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Q.
Is the check result normal?
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No action is necessary and testing is complete.
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Repair the wiring harness.
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