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Home >> Chevrolet >> 2000 >> Venture Plus >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0101: Mass Airflow Sensor System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Using scan tool, check for DTCs. If other DTCs are present, diagnose affected DTCs first. If no other DTCs are present, go to next step.
  3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see DIAGNOSTIC AIDS .
  4. DO NOT clear DTCs. Disconnect MAF sensor connector. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then stalls, go to step  6.
  5. Turn ignition off. Reconnect MAF sensor. Start engine. Monitor MAF signal on scan tool. Slowly increase engine speed to 3000 RPM. If MAF sensor signal increases with engine RPM, go to step  7. If MAF sensor signal does not increase with engine RPM, go to next step.
  6. Diagnose MAP sensor circuit. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. After repairs, go to step  20.
  7. Turn ignition on. Ensure throttle is closed. Using scan tool, observe throttle angle parameter. If scan tool indicates zero percent, go to next step. If scan tool does not indicate zero percent, diagnose using DTC P0121. Go to DTC P0121: THROTTLE POSITION SENSOR PERFORMANCE .
  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 reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step  10.
  9. Connect test light between ignition feed circuit and ground circuit terminals 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 reading is less than 4.5 volts, go to step  14. If voltage reading is not less than 4.5 volts, go to next step.
  11. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, check voltage between ground and signal circuit terminal at MAF sensor harness connector. If voltage reading is about zero volts, go to step  20. If voltage reading is not about zero volts, go to step  17.
  12. Using a test light connected to ground, probe ignition feed circuit terminal 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  20. If connection is okay, go to step  18.
  14. Check MAF sensor signal circuit for excessive resistance between PCM and MAF sensor connectors. Check for excessive resistance in sensor ground circuit. Check for MAF signal circuit shorted to sensor ground circuit. Check for poor connection at PCM. Repair as necessary. After repairs, go to step  20. If circuits or connections are okay, go to step  19.
  15. Locate and repair open in MAF sensor ground circuit. After repairs, go to step  20.
  16. Locate and repair open or excessive resistance in MAF sensor ignition feed circuit. After repairs, go to step  20.
  17. Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step  20.
  18. Replace MAF sensor. After replacing sensor, go to step  20.
  19. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  20. Using scan tool, review and record FAILURE RECORDS data. Clear DTCs. Start engine and operate vehicle as close to conditions recorded in FAILURE RECORDS as possible. Monitor SPECIFIC DTC info for this DTC. If scan tool indicates that this DTC failed this ignition, go to step  2. If scan tool does not indicate that this DTC failed this ignition, system is okay.
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