[55B] AUTOMATIC AIR CONDITIONER - - TROUBLESHOOTING - SYMPTOM PROCEDURES - INSPECTION PROCEDURE 10: Malfunction of the A/C-ECU power supply system.PRINT PAGE / INDEX / PRIOR / NEXT
INSPECTION PROCEDURE 10: Malfunction of the A/C-ECU power supply system.
CIRCUIT OPERATION
The A/C-ECU power system may be defective if the air conditioner, rear window defogger, and outside/inside air selection damper motor all do not operate normally.
TROUBLESHOOTING HINTS
  • Damaged the wiring harness or connectors
  • Malfunction of the A/C-ECU
DIAGNOSIS
Step 1. Measure the voltage at A/C-ECU connector C-26.
  1. Disconnect A/C-ECU connector C-26 and measure the voltage at the harness side.
  1. Turn the ignition switch to the "ON" position.
  1. Measure the voltage between terminal 28 and earth.
    2. OK: System voltage
Q: Is the check result normal?
YES:  Go to Step 4.
NO:  Go to Step 2.
Step 2. Connector check: A/C-ECU connector C-26
Q: Is the check result normal?
YES:  Go to Step 3.
NO:  Repair or replace the connector.
Step 3. Check the wiring harness between A/C-ECU connector C-26 (terminal 28) and the ignition switch (IG2).
NOTE: Prior to the wiring harness inspection, check junction block connectors C-205 and C-203, and repair if necessary.
Q: Is the check result normal?
YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.
Step 4. Measure the resistance at A/C-ECU connector C-26 in order to check the earth circuit to the A/C-ECU.
  1. Disconnect A/C-ECU connector C-26, and measure at the wiring harness side.
  1. Measure the resistance between terminal 27 and earth.
    2. OK: 2 ohms or less
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Go to Step 5.
Step 5. Connector check: A/C-ECU connector C-26
Q: Is the check result normal?
YES:  Go to Step 6.
NO:  Repair or replace the connector.
Step 6. Check the wiring harness between A/C-ECU connector C-26 (terminal 27) and the earth.
Q: Is the check result normal?
YES:  Replace the automatic air conditioner control panel (A/C-ECU).
NO:  Repair the wiring harness.
Step 7. Measure the voltage at A/C-ECU connector C-27.
  1. Disconnect A/C-ECU connector C-27 and measure the voltage at the harness side.
  1. Measure the voltage between terminal 3 and earth.
    2. OK: System voltage
Q: Is the check result normal?
YES:  Replace the automatic air conditioner control panel (A/C-ECU).
NO:  Go to Step 8.
Step 8. Connector check: A/C-ECU connector C-27.
Q: Is the check result normal?
YES <Except vehicles for South Africa>:  Go to Step 9.
YES <Vehicles for South Africa>:  Go to Step 10.
NO:  Repair or replace the connector.
Step 9. Check the wiring harness between A/C-ECU connector C-27 (terminal 3) and battery.
NOTE: Prior to the wiring harness inspection, check intermediate connector C-125, A-14 and junction block connector C-204, and repair if necessary.
Q: Is the check result normal?
YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.
Step 10. Check the wiring harness between A/C-ECU connector C-27 (terminal 3) and battery.
NOTE: Prior to the wiring harness inspection, check intermediate connector C-116 and joint connector C-02, and repair if necessary.
Q: Is the check result normal?
YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.
[55B] AUTOMATIC AIR CONDITIONER - - TROUBLESHOOTING - SYMPTOM PROCEDURES - INSPECTION PROCEDURE 10: Malfunction of the A/C-ECU power supply system.PRINT PAGE / INDEX / PRIOR / NEXT
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