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Home >> Subaru >> 2021 >> Ascent Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (1 Of 4) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0103: Mass Or Volume Air Flow Sensor "A" Circuit High >> Notes

DTC P0103: Mass Or Volume Air Flow Sensor "A" Circuit High: Notes

  1. DTC detecting condition: 

    Immediately at fault recognition

    Trouble symptom: 

    • Improper idling
    • Engine stalls.
    • Poor driving performance
    NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Basic Diagnostic Procedure>PROCEDURE .
  1. CHECK DATA MONITOR  .
    1. Start the engine.
    2. Using the Subaru Select Monitor, read the value in [Air Flow Rate from Mass Air Flow Sensor].
      NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (diag)>DATA MONITOR .

    Is the value of [Mass Air Flow] 320.5 g/s (42.4 lb/min) or more?

    Yes  : Go to  2.

    No  : Even if DTC is detected, the circuit has returned to a normal condition at this time.

    Reproduce the failure, and then perform the diagnosis again.

    NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
  2. CHECK FOR POOR CONTACT  .

    Check for poor contact of mass air flow and intake air temperature sensor connector.

    Is there poor contact of mass air flow and intake air temperature sensor connector?

    Yes  : Repair the poor contact of mass air flow and intake air temperature sensor connector.

    No  : Replace the mass air flow and intake air temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>MASS AIR FLOWS AND INTAKE AIR TEMPERATURE SENSOR .