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Home >> Mitsubishi >> 2014 >> Lancer ES Sportback >> Repair and Diagnosis >> External Pages >> Different car >> Section 62 (Heating, Air Conditioning & Ventilation - With Diagnostics) >> Automatic A/C Diagnosis >> Symptom Procedures >> INSPECTION PROCEDURE 11: Heater controller assembly (A/C-ECU) power supply system >> Diagnosis

INSPECTION PROCEDURE 11: Heater controller assembly (A/C-ECU) power supply system: Diagnosis

WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.
  1. STEP 1. Check whether the DTC is stored. 

    Check that the ETACS-ECU has not stored a diagnostic trouble code.

    Q: Is the diagnostic trouble code stored? 

    1. YES:  Carry out the diagnostic trouble code procedures. Refer to DIAGNOSTIC TROUBLE CODE CHART .
    2. NO:  Go to Step 2.
  2. STEP 2. Measure the voltage at the heater controller assembly (A/C-ECU) connector. 
    1. Disconnect the connector, and measure at the wiring harness side.
    2. Ignition switch: ON
    3. Voltage between terminal No. 20 and body ground

      OK: System voltage 

    Q: Is the check result normal? 

    1. YES:  Go to  Step 4.
    2. NO:  Go to Step 3.
  3. STEP 3. Check of open circuit in heater controller assembly (A/C-ECU) IG1 line between ETACS-ECU connector and heater controller assembly (A/C-ECU) connector. 

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
    2. NO:  Repair the connector(s) or wiring harness.
  4. STEP 4. Measure the voltage at the heater controller assembly (A/C-ECU) connector. 
    1. Disconnect the connector, and measure at the wiring harness side.
    2. Voltage between terminal No. 19 and body ground

      OK: System voltage 

    Q: Is the check result normal? 

    1. YES:  Go to  Step 6.
    2. NO:  Go to Step 5.
  5. STEP 5. Check of open circuit in heater controller assembly (A/C-ECU) B/UP line between ETACS-ECU connector and heater controller assembly (A/C-ECU) connector. 
    NOTE: Prior to the wiring harness inspection, check joint connector and repair if necessary.

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
    2. NO:  Repair the connector(s) or wiring harness.
  6. STEP 6. Measure the resistance at the heater controller assembly (A/C-ECU) connector. 
    1. Disconnect the connector, and measure at the wiring harness side.
    2. Resistance between terminal No. 18 and body ground

      OK: Continuity exists (2 Ω or less) 

    Q: Is the check result normal? 

    1. YES:  Replace the heater controller assembly (A/C-ECU).
    2. NO:  Go to Step 7.
  7. STEP 7. Check of open circuit in heater controller assembly (A/C-ECU) E line between heater controller assembly (A/C-ECU) connector and ground J/C (DASH) connector. 

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
    2. NO:  Repair the connector(s) or wiring harness.
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