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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 116 (Engine Controls - Self-Diagnostics - 4.0L) >> Diagnostic Tests >> DTC P0102: Mass Airflow Sensor Circuit Low Frequency >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Start engine. Using scan tool, check MAF sensor frequency parameter. Is frequency reading less than 1135 Hz? If yes, go to step  4. If no, go to next step.
  3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. See CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Using scan tool, observe MAF sensor frequency. Move MAF sensor harness and connector. Does the movement of the harness or connector affect MAF sensor frequency? If yes, go to step  25. If no, go to next step.
  5. Turn ignition off. Inspect for a restricted air intake duct, collapsed air intake duct, misaligned air intake duct, dirty air filter element, deteriorating air filter element, objects blocking the MAF sensor air inlet screen, debris on sensing elements of MAF sensor, vacuum leak downstream of MAF sensor, MAF sensor installed backwards or a restricted exhaust system. Did you find and correct the condition? If yes, go to step  30. If no, go to next step.
  6. Inspect fuse in the ignition 1 voltage circuit of MAF sensor. Is fuse open? If yes, go to step  12. If no, go to next step.
  7. Disconnect MAF sensor harness connector. Turn ignition on, with engine off. Connect a test lamp between the ignition 1 voltage circuit of MAF sensor and a good ground. Does test lamp illuminate? If yes, go to next step. If no, go to step  18.
  8. Connect test lamp between MAF sensor ignition 1 voltage circuit and MAF sensor ground circuit. Does the test lamp illuminate? If yes, go to next step. If no, go to step  19.
  9. Measure voltage from MAF sensor signal circuit to a good ground. Is voltage about 5 volts? If yes, go to next step. If no, go to step  11.
  10. Connect a 3-amp fused jumper wire between signal circuit of the MAF sensor harness connector and a good ground. Start engine. Observe the 5-volt reference 1 parameter and the 5-volt reference 2 parameter with a scan tool. Does the scan tool display OK for both parameters? If yes, go to step  26. If no, go to step  23.
  11. Is voltage less than 4.5 volts? If yes, go to step  13. If no, go to step  15.
    12. NOTE: The ignition 1 voltage circuit of the MAF sensor is spliced to other components of the vehicle.
  12. Test for continuity between MAF sensor ignition 1 voltage circuit and ground. Does the Digital Multimeter (DMM) indicate continuity? If yes, go to step  17. If no, go to step  26.
  13. Turn ignition off. Disconnect PCM. Test the signal circuit between PCM and MAF sensor for a high resistance or open circuit. Does the DMM indicate continuity? If yes, go to next step. If no, go to step  20.
  14. Test for continuity from the MAF sensor signal circuit to ground. Does the DMM indicate continuity? If yes, go to step  21. If no, go to step  16.
    15. NOTE: Disconnecting the PCM connectors may eliminate the short to voltage if signal circuit is shorted to another PCM circuit.
  15. Turn ignition off. Disconnect PCM. Turn ignition on, with engine off. Measure the voltage from the MAF sensor signal circuit to a good ground. Is voltage about 0 volts? If yes, go to next step. If no, go to step  22.
  16. Test for continuity at the PCM harness connector from the MAF sensor signal circuit to all other circuits at both PCM connectors. Does the DMM indicate continuity between any other circuit? If yes, go to step  24. If no, go to step  27.
  17. Repair the short to ground in the MAF sensor ignition 1 voltage circuit. Replace fuse, if necessary. After repairs, go to step  30.
  18. Repair the open in MAF sensor ignition 1 voltage circuit. After repairs, go to step  30.
  19. Repair high resistance or an open in ground circuit of MAF sensor. After repairs, go to step  30.
  20. Repair high resistance or an open in signal circuit of MAF sensor. After repairs, go to step  30.
  21. Repair short to ground in MAF sensor signal circuit. After repairs, go to step  30.
  22. Repair short to voltage in MAF sensor signal circuit. After repairs, go to step  30.
  23. Repair short between the MAF sensor signal circuit and circuit for which the DTC set. After repairs, go to step  30.
  24. Repair circuits that are shorted together. After repairs, go to step  30.
  25. Repair the harness or connections as needed. After repairs, go to step  30.
  26. Test for an intermittent and for a poor connection at MAF sensor. Did you find and correct the condition? If yes, go to step  30. If no, go to step  28.
  27. Test for an intermittent and for a poor connection at PCM. Did you find and correct the condition? If yes, go to step  30. If no, go to step  2.
  28. Replace MAF sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. When complete, go to step  30.
  29. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  30. Use the scan tool in order to clear the DTCs. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  31. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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