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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 P0502: Vehicle Speed Sensor Circuit Low Input
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DTC P0502: Vehicle Speed Sensor Circuit Low Input

  1. OUTLINE OF DIAGNOSIS 
    • Detect the open or short circuit of vehicle speed.
    • Judge NG when the vehicle speed is low while the vehicle speed is assumed to be high.
  2. ENABLE CONDITION 
    ENABLE CONDITION

    Secondary Parameters Enable Conditions
    None  
  3. GENERAL DRIVE CYCLE 

    Always perform the diagnosis continuously.

  4. DIAGNOSTIC METHOD 

    Judge NG when the time of completing the malfunction criteria below becomes more than time needed for diagnosis. Judge OK when the vehicle speed is more than 4 km/h (2.5 MPH) and less than 224 km/h (140 MPH).

    Judgment Value 

    JUDGMENT VALUE

    Malfunction Criteria Threshold Value
    Low side diagnosis (1)   
    Cumulative time when the malfunction criteria below are completed "GREATER THAN EQUAL TO" 0 seconds
    Idle switch OFF
    Injector pulse "GREATER THAN EQUAL TO" 2.5 milliseconds
    Engine speed "GREATER THAN EQUAL TO" 2,800 rpm
    Neutral switch OFF
    Vehicle speed signal (353 mS) <1

    Time Needed for Diagnosis: 

    Low side: 20 seconds

    Malfunction Indicator Light Illumination:  Illuminates as soon as malfunction occurs.

  5. DTC CLEAR CONDITION 
    • When the OK idling cycle is 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 

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