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Home >> Subaru >> 2004 >> Forester XS, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4SO) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0720: Output Speed Sensor Circuit
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DTC P0720: Output Speed Sensor Circuit

  1. OUTLINE OF DIAGNOSIS 

    Judge NG when an abnormal large signal is input to the front vehicle speed sensor, or no signal is input to the rear vehicle speed sensor.

  2. COMPONENT DESCRIPTION 

    This vehicle speed sensor (output shaft speed sensor) is installed to the outside of transmission case.

    This sensor detects the front wheel speed, and transmits the sine wave signal (16 pulses per rev.) to TCM. TCM converts the signal to pulse signal, and transmits to both of the ECM and the combination meter.

  3. ENABLE CONDITION 
    ENABLE CONDITION

    Secondary Parameters Enable Conditions
    Vehicle speed "GREATER THAN EQUAL TO" 0km/h(12MPH)
  4. GENERAL DRIVING CYCLE 

    Perform the diagnosis continuously with more than 20 km/h (12 MPH) vehicle speed.

  5. DIAGNOSTIC METHOD 

    Judgment Value 

    JUDGMENT VALUE

    Malfunction Criteria Threshold Value
    Vehicle speed sensor signals/1 second "GREATER THAN EQUAL TO" 4698 or no signal

    Time Needed for Diagnosis:  63.75 seconds

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

  6. DTC CLEAR CONDITION 
    • When the OK idling cycle was completed 40 times in a row
    • When "Clear Memory" was performed
  7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION 
    • When the OK driving cycle was completed 3 times in a row
    • When "Clear Memory" was performed
  8. FAIL SAFE 
    • Use the normal vehicle speed sensor signal when either of them is normal.
    • Use the vehicle speed calculated from the current gear position and turbine speed when both front and rear wheels are troubled.
  9. ECM OPERATION AT DTC SETTING 

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