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Home >> Chevrolet >> 1996 >> Astro Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0102 - MAF Sensor Circuit Low Frequency >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. Retrieve and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
  2. Start engine. With engine at idle, use scan tool to read MAF value. If MAF value is less than 2 grams per second, go to step 4). If value is 2 grams per second or greater, go to next step.
  3. Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAIL RECORDS data. Operate vehicle within conditions noted in FAIL RECORD data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0102 FAILED THIS IGN, go to next step. If DTC P0102 FAILED THIS IGN is not displayed, see DIAGNOSTIC AIDS.
  4. Check for MAF sensor inlet screen blockage. Check for vacuum leaks at intake manifold, throttle body or EGR valve flange and pipes. Check for crankcase valve faulty, missing or incorrectly installed. Repair faulty conditions as necessary and go to step 14). If no faulty conditions exist, go to next step.
  5. 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 about 5 volts, go to step 9).
  6. Connect a test light between MAF sensor harness connector ignition feed and ground circuits. If test light illuminates, go to step 8). If test light does not illuminate, go to next step.
  7. Connect test light between MAF sensor harness connector ignition feed circuit and battery ground. If test light illuminates, go to step 10). If test light does not illuminate, go to step 11).
  8. Check for faulty connection at MAF sensor. Repair connection as necessary and go to step 14). If connection is okay, go to step 12).
  9. Check MAF sensor signal circuit between VCM and MAF sensor for open or short. Repair signal circuit as necessary and go to step 14). If signal circuit is okay, go to step 13).
  10. Locate and repair open in the MAF sensor ground circuit and go to step 14).
  11. Locate and repair open MAF sensor ignition feed circuit and go to step 14).
  12. Replace MAF sensor and go to step 14).
  13. Replace VCM. Program replacement VCM using required equipment. Go to next step.
  14. Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0102. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2).
  15. Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.
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