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Home >> Pontiac >> 2000 >> Firebird Formula, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 5.7L >> Diagnostic Tests >> DTC P0101: MAF System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
    NOTE: If any MAP sensor related DTCs are set, diagnose these DTCs first. See appropriate DTC test.
  2. Start engine. Using scan tool, monitor MAP sensor voltage. If voltage reading is 0.8-4.0 volts, go to next step. If voltage reading is not 0.8-4.0 volts, diagnose using DTC P0107 or P0108. See DTC P0107: MAP SENSOR CIRCUIT LOW VOLTAGE  or DTC P0108: MAP SENSOR CIRCUIT HIGH VOLTAGE .
  3. Turn ignition off. Remove MAP sensor from intake manifold, leaving wiring harness connected. Install a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Observe MAP sensor reading on scan tool while applying vacuum. Each one in. Hg applied should result in 3-4 kPa decrease. Value should change smoothly with each increase in vacuum. If MAP value changed smoothly without any erratic reading, go to next step. If reading is erratic, go to step  19.
  4. Apply up to 20 in. Hg of vacuum to MAP sensor. If MAP sensor reading on scan tool is 34 kPa or less, go to next step. If MAP sensor reading is not as specified, go to step  19.
  5. Remove vacuum source from MAP sensor. If MAP sensor reading returns to original value observed in step  3, go to next step. If reading does not return to original value, go to step  19.
  6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function and enter DTC P0101. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see DIAGNOSTIC AIDS .
  7. Check for blockage in MAF sensor inlet screen, intake manifold leak, vacuum leak at throttle body, leak at EGR valve flange and pipes, or faulty PCV valve. Repair or replace as necessary. After repairs, go to step  21. If no problem is found, go to next step.
  8. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, check voltage between ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step  10.
  9. Connect a test light between ignition positive feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step  13. If test light does not illuminate, go to step  12.
  10. If voltage is less than 4.5 volts, go to step  14. If voltage is not as specified, go to next step.
  11. Turn ignition off. Disconnect PCM harness connector C2 (Red). Turn ignition on, with engine off. Using DVOM, check voltage between ground and MAF sensor signal circuit. If voltage is about zero volts, go to step  20. If voltage is not as specified, go to step  17.
  12. Using a test light connected to battery ground, probe ignition positive feed circuit at MAF sensor harness connector. If test light illuminates, go to step  15. If test light does not illuminate, go to step  16.
  13. Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step  21. If connection is okay, go to step  18.
  14. Check MAF signal circuit between PCM and MAF sensor for an open, short to ground or short to MAF sensor ground circuit. Repair as necessary. After repairs, go to step  21. If circuit is okay, go to step  20.
  15. Locate and repair open in MAF sensor ground circuit. After repairs, go to step  21.
  16. Locate and repair open in MAF sensor ignition positive feed circuit. After repairs, go to step  21.
  17. Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step  21.
  18. Replace MAF sensor. After replacing sensor, go to step  21.
  19. Replace MAP sensor. After replacing sensor, go to step  21.
  20. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  21. Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select SPECIFIC DTC, and then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step  2.
  22. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.
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