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Home >> Subaru >> 2004 >> Forester XT, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0851: Neutral Switch Input Circuit Low (At Model)
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DTC P0851: Neutral Switch Input Circuit Low (At Model)

  1. OUTLINE OF DIAGNOSIS 

    Detect the open or short circuit of the neutral SW.

    Judge NG when the ECM neutral terminal input differs from the reception data from TCM.

  2. ENABLE CONDITION 
    ENABLE CONDITION CHART

    Secondary Parameters Enable Conditions
    Ignition switch ON
    Battery voltage "GREATER THAN EQUAL TO" 10.9 V
    After starting the engine 2 seconds or more
    Starter switch OFF
  3. GENERAL DRIVING CYCLE 

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

  4. DIAGNOSTIC METHOD 

    Judge NG when the continuous time of completing the malfunction criteria below becomes more than 6.5 seconds. Judge OK and clear NG when the malfunction criteria below are not completed.

    Judgment Value 

    JUDGMENT VALUE CHART

    Malfunction Criteria Threshold Value
    Neutral switch signal when park/neutral = "ON" & any other switches = "OFF" on AT OFF

    Time Needed for Diagnosis:  6.5 seconds

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

  5. DTC CLEAR CONDITION 
    • When the OK idling cycle was completed 40 times in a row
    • When "Clear Memory" was performed
  6. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION 
    • When the OK driving cycle was completed 3 times in a row
    • When "Clear Memory" was performed
  7. FAIL SAFE 

    None

  8. ECM OPERATION AT DTC SETTING 

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