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Home >> Subaru >> 2004 >> Forester X, Automatic >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4SO) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0066: Air Assisted Injector Control Circuit Or Circuit Low
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DTC P0066: Air Assisted Injector Control Circuit Or Circuit Low

  1. OUTLINE OF DIAGNOSIS 

    Detect the open or short circuit of AAI solenoid valve. Judge NG when the ECM output level is different from actual terminal level.

  2. COMPONENT DESCRIPTION 
    Fig 1: Air Assisted Injector Control Circuit Diagram (Low)
    G03320344Courtesy of SUBARU OF AMERICA, INC.
  3. ENABLE CONDITION 
    ENABLE CONDITIONS

    Secondary Parameters Enable Conditions
    Engine speed "GREATER THAN EQUAL TO" 500 rpm
    Battery voltage "GREATER THAN EQUAL TO" 10.9 V
    After engine starting 2 seconds or more
    Ignition switch ON
  4. GENERAL DRIVING CYCLE 

    Perform the diagnosis continuously in 2 seconds after starting the engine.

  5. DIAGNOSTIC METHOD 
    • Abnormality Judgment 

      Judge NG when the cumulative time until completing the malfunction criteria below becomes more than the time needed for diagnosis (2.5 seconds).

      Judgment Value 

      JUDGMENT VALUE (ABNORMALITY JUDGMENT)

      Malfunction Criteria Threshold Value
      Terminal voltage level while ECM sent OFF signal Low level

      Time Needed for Diagnosis:  2.5 seconds

      Malfunction Indicator Light Illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.

    • Normality Judgment 

      Judge OK and clear the NG when the malfunction criteria below are completed.

      Judgment Value 

      JUDGMENT VALUE (NORMALITY JUDGMENT)

      Malfunction Criteria Threshold Value
      Terminal voltage level while ECM sent OFF signal High level
  6. DTC CLEAR CONDITION 
    • When the OK idling cycle is completed 40 times in a row
    • When "Clear Memory" was performed
  7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION 
    • When the OK driving cycle is completed 3 times in a row
    • When "Clear Memory" was performed
  8. FAIL SAFE 

    None

  9. ECM OPERATION AT DTC SETTING 

    Memorize the freeze frame data. (For test mode $02)