Inspection Procedure 17: A/C-ECU power supply system
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If a power supply is not provided to the
A/C-ECU, the A/C-ECU power supply system or the earth system
may be defective.
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- Malfunction of the A/C-ECU
- Damaged harness wires and connectors
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STEP 1. Connector check: D-08 A/C-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 connector.
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STEP 2. Voltage measurement at the D-08 A/C-ECU
connector.
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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)measure the voltage between terminal 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-08 A/C-ECU connector
terminal No.20 and the ignition switch (IG2).
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Prior to the wiring harness inspection, check
junction block connector D-403 and D-401, and repair if
necessary.
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- Check the blower relay 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 Cope
with Intermittent Malfunction  ).
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Repair
the wiring harness.
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STEP 4. Voltage measurement at D-08 A/C-ECU connector.
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(1)Remove the relay, and measure at the junction block
side.
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(2)Voltage between terminal 19 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-08 A/C-ECU connector
terminal No.19 and fusible link (1).
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| note |
Prior to the wiring harness inspection, check
intermediate connectors D-241 and joint connector D-34, and repair if
necessary.
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- Check the A/C-ECU 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 Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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STEP 6. Resistance measurement at the D-08 A/C-ECU
connector.
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(1)Disconnect the connector, and measure at the wiring
harness side.
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(2)Continuity between terminal 9 and body
earth
OK: Continuity (Less than 2 ohms)
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(3)Continuity between terminal 7 and body
earth
OK: Continuity (Less than 2 ohms)
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Q.
Is the check result normal?
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Replace the A/C-ECU.
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Go to Step 7.
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STEP 7. Check the wiring harness between D-08 A/C-ECU connector
terminal No.9, 7 and body earth.
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| note |
Prior to the wiring harness inspection, check joint
connector D-34, and repair if necessary.
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- Check the A/C-ECU earth 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 Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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