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Home >> Saab >> 2001 >> 9-5 Base, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Fault Code Diagnosis >> P0101: Mass Air Flow Circuit. Performance Problems. >> Fault Isolation Procedure

Fault Isolation Procedure

  1. Checking for air leakage: Check that there are no major air leaks between the mass air flow sensor and the throttle. If the system is airtight, go to step  3, otherwise go to next step.
  2. Final check:
    • Rectify the air leakage.
    • Contact ECM.
    • Start the engine and run it at idling speed.
    • Test value: Airmass Deviation from Calculated.
      NOTE: If the power supply to the control module is interrupted, e.g. if a battery cable is removed, the engine must be run until warm and then the ignition turned off for at least 5 seconds before the car is test driven.
    • Drive the car in third gear with a steady load at about 45 MPH (70 KPH) for 30 seconds.
    • Drive the car in fourth gear with a steady load at about 45 MPH (70 KPH) for 30 seconds.
    • Stop the car and turn off the ignition. Wait 5 seconds. Start the car and continue test driving.
    • Drive the car in third gear with a steady load at about 45 MPH (70 KPH) for 30 seconds.
    • Drive the car in fourth gear with a steady load at about 45 MPH (70 KPH) for 30 seconds.
    If the diagnostic tool shows -10% to 10%, the fault has been rectified. If the value is incorrect, continue checking for leaks. If no leaks can be found, the ECM is faulty.
    NOTE: If you've replaced the mass air flow sensor and the fault is still present, be sure to change it back out.
  3. Changing components: Change the mass air flow sensor. When finished, go to step  2.
Fig 1: Overview, Mass Air Flow
G00207342Courtesy of SAAB-SCANIA OF AMERICA, INC.
Fig 2: Mass Air Flow Circuit
G00207341Courtesy of SAAB-SCANIA OF AMERICA, INC.
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