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Home >> Ford >> 2002 >> Taurus SES, 3.0 S >> Repair and Diagnosis >> External Pages >> Different car >> Section 194 (Engine Controls - Self-Diagnostics - 6.0L (99P F450/550) Diesel) >> System Tests >> Test J: Mass Air Flow Sensor >> Testing

Test J: Mass Air Flow Sensor: Testing

WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: The Powertrain Control Module (PCM) harness connectors must be properly seated and the connector latch properly attached to eliminate possible driveability concerns or a no-start condition. Installing PCM connectors on an angle may cause a bad connection, misdiagnosis and damaged components. Install the connector on where the lever pivots and seats itself. Apply light pressure to get the connector into position on the PCM lever to fully seat the connector.
NOTE: When the PCM engine harness connector is disconnected additional DTCs will be set. All DTCs must be cleared before returning the vehicle to service.

  1. 1) Preliminary Diagnosis For DTCs P006A, P0101, P0102 & P0103

    Perform the visual inspection. Connect the scan tool. Retrieve and record all DTCs. Record freeze frame data. Clear all DTCs. Perform the KOEO ON-DEMAND SELF-TEST  under QUICK TEST. Perform the KOER ON-DEMAND SELF-TEST  under QUICK TEST. Are DTCs P006A, P0101, P0102 or P0103 present? If yes, for P006A, go to step  13). For P0101, go to next step. For P0102, go to step  4). For P0103, go to step  8). If no, unable to duplicate condition. Check for restriction in air flow. Check for loose connection, damaged or corroded terminals or pins. Wiggle harness attempting to recreate the fault. See TROUBLE SHOOTING - NO CODES - 6.0L DIESEL article if driveability concern exists.

  2. 2) DTC P0101

    Possible causes are:
    • Restricted air flow.
    • Faulty MAF.
    • Contaminated sensor.
    • Unmetered air flow into engine.
    • Faulty PCM.

    Inspect air intake for restriction. Check for air leak into air intake snorkel. Check MAF sensor for contamination. Is any restriction or contamination present? If yes, remove restriction and repair system as necessary. Clear DTCs and retest the system. If no, go to next step.

  3. 3) Check MAF Output Signal To PCM

    Access MAF PIDs. Engine running. Monitor MAF PID volts at idle. Increase idle to approximately 2,500 RPM while monitoring PID. Is MAF PID value 1.4 to 1.8 volts with engine idling and 1.9 to 2.1 volts at 2,500 RPM? If yes, install a new PCM. Restore the vehicle. Clear DTCs and retest the system. If no, install a new MAF sensor. Restore the vehicle. Clear DTCs and retest the system.

  4. 4) DTC P0102

    Possible causes are:
    • Restricted air flow.
    • MAF disconnected.
    • VPWR open to MAF.
    • PWR GND open to MAF.
    • MAF RTN signal open.
    • MAF signal shorted to ground.
    • Mechanical failure.
    • Faulty MAF.
    • Faulty PCM.

    Inspect air intake for restrictions. Key off. Disconnect the MAF harness connector. Key on. Measure the voltage between the MAF sensor connector terminal No. 2 (VPWR circuit) and MAF sensor connector terminals No. 1 and 3 (PWR GND and signal return circuit). See Figure. Is the voltage measurement greater than 10.5 volts at each circuit? If yes, go to next step. If no, repair open in the vehicle power or vehicle ground circuit. Restore the vehicle. Clear DTCs and retest the system.

  5. 5) Check MAF Sensor Signal Circuit For A Short To Ground

    Key off. Disconnect the PCM body harness electrical connector C1381A. Measure the resistance between MAF sensor harness connector terminal No. 5 (signal circuit) and ground. Is the resistance greater than 10,000 ohms? If yes, go to next step. If no, repair short to ground in signal circuit. Restore the vehicle. Clear DTCs and retest the system.

  6. 6) Check MAF Sensor Signal Circuit For An Open

    Measure the resistance between MAF sensor harness connector terminal No. 5 (signal circuit) and PCM body harness connector C1381A terminal No. 42. See CONTROL MODULE CONNECTOR IDENTIFICATION . Is the resistance less than 0.5 ohm? If yes, go to next step. If no, repair open in signal circuit. Restore the vehicle. Clear DTCs and retest the system.
    7. NOTE: This step may cause DTC P0103 to set.

  7. 7) Check MAF Sensor Circuits
    Reconnect the PCM body harness electrical connector. Key on, engine off. Access MAF VOLT PID. Record MAF VOLT PID reading. Install a jumper wire between the MAF sensor connector terminal No. 5 (signal circuit) and 2 (MAF VPWR circuit). Does the MAF PID change from less than 0.04 volt to greater than 4.5 volts? If yes, install a new MAF sensor. Restore the vehicle. Clear DTCs and retest the system. If yes, install a new PCM. Restore the vehicle. Clear DTCs and retest the system.

  8. 8) DTC P0103

    Possible causes are:
    • Restricted inlet air flow.
    • MAF signal circuit shorted to power.
    • Open ground circuit.
    • Faulty MAF.
    • Faulty PCM.

    Disconnect air inlet and check for restrictions. Are any restrictions found? If yes, remove restrictions in air flow. Restore the vehicle. Clear DTCs and retest the system. If no, go to next step.

  9. 9) Induce Opposite Failure

    Disconnect the MAF sensor electrical connector. Perform the KOEO ON-DEMAND SELF-TEST  under QUICK TEST. Is DTC P0102 present? If yes, restore the vehicle. Clear DTCs. go to step  12). If no, go to next step.

  10. 10) Check MAF Sensor Signal Circuit For A Short To Voltage

    Disconnect the PCM body harness electrical connector C1381A. Measure the voltage between MAF sensor connector terminal No. 5 (signal circuit) and ground. See Figure. Is the voltage less than 0.2 volt? If yes, go to next step. If no, repair short to voltage in signal circuit. Restore the vehicle. Clear DTCs and retest the system.

  11. 11) Check MAF Return Circuits For An Open

    Key off. Measure the resistance between MAF sensor harness connector terminal No. 1 (signal return circuit) and PCM body harness connector C1381A terminal No. 33, and between the MAF sensor harness connector C1381A terminal No. 4 and PCM body harness connector C1381A terminal No. 21. See CONTROL MODULE CONNECTOR IDENTIFICATION . Is the resistance less than 0.5 ohm? If yes, install a new PCM. Restore the vehicle. Clear DTCs and retest the system. If no, repair open in signal return circuit. Restore the vehicle. Clear DTCs and retest the system.

  12. 12) Check The MAF Signal To The PCM

    Access MAF PID. Key ON, engine running. Monitor and record MAF PID voltage at idle. Increase engine speed to 2500 RPM. Record MAF PID voltage. Is MAF PID value 1.2-1.8 volts with engine idling and 2.4-3.0 volts at 2500 RPM? If yes, unable to duplicate condition. Concern may be due to water intrusion. If no, Install new MAF sensor. Restore vehicle. Clear DTCs and retest system.
    13. NOTE: Diagnose all other DTCs before P006A.

  13. 13) Check For Leaks
    Inspect MAF sensor for water or dirt and dust contamination. Check for leaks or restrictions in intake air system. Check for leaks in exhaust system. Check for leaks in EGR system. Is a concern present? If yes, repair as necessary. Clear DTCs and repeat self-test. If no, go to next step.
    14. NOTE: Diagnose all other DTCs before P006A.
    NOTE: Most weather reports are a local barometric pressure that has been corrected to sea level. The BARO PID reports actual barometric pressure for the altitude where vehicle is being diagnosed. Local weather conditions will change local barometric pressure by several inches of mercury.

  14. 14) Check The MAP And BARO Sensors
    Key ON, engine Off. Monitor and record MAP and BARO PID values. Are MAP and BARO PID values within 6.9 kPa (1 psi) of atmospheric pressure? If yes, install new MAF sensor. Restore vehicle. Clear DTCs and retest system. If no, for BARO sensor concerns, go to TEST H: BAROMETRIC PRESSURE SENSOR . For MAP sensor concerns, go to TEST E: MANIFOLD ABSOLUTE PRESSURE SENSOR .
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