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Home >> Buick >> 1996 >> LeSabre Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0101 - MAF Sensor System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. If DTC P1635 is also set, go to DTC P1635. If DTC is not set, go to next step.
  3. Turn ignition on, engine off. Using scan tool, read and record FAIL RECORDS data. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0101 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0101 FAILED THIS IGN, go to DIAGNOSTIC AIDS.
  4. Ignition on. Observe MAP and BARO parameter on scan tool. If reading is 65-105 kPa, go to next step. If not, go to step 8).
  5. Start engine. Observe MAP sensor display on scan tool with engine idling. If display is 29-48 kPa, go to next step. If not, go to step 7).
  6. Observe MAP sensor display on scan tool while slowly increasing engine speed to 3000 RPM. If MAP value increases with increase in RPM, go to step 9). If not, go to step 8).
  7. Check for throttle body inlet screen blockage. Check for vacuum leaks at intake manifold, throttle body, or EGR valve flange and pipes. Check for PCV valve faulty, missing or incorrectly installed. Repair faulty conditions as necessary and go to step 22). If no faulty conditions exist, go to step 9).
  8. Replace MAP sensor. After repair, go to step 22).
  9. Turn ignition on, throttle closed. Using scan tool, read THROTTLE AT IDLE. If scan tool displays YES, go to next step. If scan does not display YES, go to DTC P0121.
  10. Turn ignition off. Disconnect MAF sensor harness connector. Turn ignition on, engine off. Using a DVOM, check voltage between MAF sensor harness connector signal circuit and chassis ground. If voltage is about 5 volts, go next step. If voltage is not as specified, go to step 12).
  11. Connect a test light between MAF sensor harness connector ignition feed and ground circuits. If test light illuminates, go to step 15). If test light does not illuminate, go to step 14).
  12. If voltage is less than 4.5 volts, go to step 16). If voltage is 4.5 volts or more, go to next step.
  13. Turn ignition off. Disconnect PCM connectors. Turn ignition on, engine off. Check voltage between PCM harness connector MAF signal circuit and chassis ground. If voltage reading is zero volts, go to step 21). If voltage is not zero volts, go to step 19),
  14. Connect test light between MAF sensor harness connector ignition feed circuit and chassis ground. If test light illuminates, go to step 17). If test light does not illuminate, go to step 18).
  15. Check for faulty connection at MAF sensor. Repair connection as necessary and go to step 22). If connection is okay, go to step 20).
  16. Check MAF sensor signal circuit between PCM and MAF sensor for open or short. Repair signal circuit as necessary and go to step 22). If signal circuit is okay, go to step 21).
  17. Locate and repair open MAF in the sensor ground circuit and go to step 22).
  18. Locate and repair open MAF sensor ignition feed circuit and go to step 22).
  19. Locate and repair short to voltage in MAF sensor signal circuit and go to step 22).
  20. Replace MAF sensor and go to step 22).
  21. Replace PCM. Program PCM using required equipment. Go to next step.
  22. Turn ignition on, engine off. Using scan tool, read and record FAIL RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P0101. If scan tool displays DTC P0101 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P0101 FAILED THIS IGN, repair is complete.
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