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Home >> Chevrolet >> 1998 >> Astro Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0103 - MAF Sensor Circuit High Frequency >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform POWERTRAIN 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 greater than 20 gm/s, go to step 4). If MAF value is not greater than 20 gm/s, 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 that this DTC FAILED THIS IGN, go to next step. If scan tool does not indicate that this DTC FAILED THIS IGN, see DIAGNOSTIC AIDS.
  4. Turn ignition off. Disconnect MAF sensor harness connector. Start and allow engine to idle. Using scan tool, read MAF value. If value is about 0 gm/s, go to next step. If value is not 0 gm/s, go to step 7).
  5. Check for faulty connection at MAF sensor. Repair as necessary. After repairs, go to step 10). If connection is okay, go to next step.
  6. Replace MAF sensor. After replacing sensor, go to step 10).
  7. Ensure MAF sensor harness is not routed too close to high-voltage wires, such as spark plug cables, ignition coils or other high-voltage components. Reroute harness if necessary and then go to step 10). If harness routing is okay, go to next step.
  8. Check MAF sensor signal circuit connection at VCM. Repair as necessary. After repairs, go to step 10). If connection is okay, go to next step.
  9. Replace VCM. Program replacement PCM using required equipment. After replacing VCM, go to next step.
  10. 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 this DTC. Operate vehicle within conditions required to set DTC. If scan tool indicates that this DTC RAN AND PASSED, go to next step. If scan tool does not indicate that this DTC RAN AND PASSED, repeat step 2).
  11. Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no additional DTCs are displayed, system is okay.
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