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Home >> GMC >> 1997 >> Forward Control 4.3 W, L35, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 58 (Engine Controls - Tests W/Codes - 4.3L) >> Diagnostic Trouble Codes >> DTC P0103 - MAF Sensor Circuit High Frequency >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 1997 GMC Savana, 1997 Chevrolet Chevy Van, and 1997 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the F - BASIC TESTING - 4.3L article. After performing OBD system check, go to next step.
  2. Install scan tool. Start engine. With engine idling, monitor MAF display on scan tool. If MAF display is greater than 20 gm/s, go to step 4). If MAF is not greater than 20 gm/s, go to next step.
  3. Turn ignition on, with engine off. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC for DTC P0103. If scan tool indicates DTC P0103 FAILED THIS IGN?, go to next step. If scan tool does not indicate DTC P0103 FAILED THIS IGN?, see DIAGNOSTIC AIDS.
  4. Turn ignition off. Disconnect MAF sensor connector. Start engine. With engine idling, monitor MAF frequency display on scan tool. If scan tool display is zero gm/s, go to next step. If scan tool display is not zero gm/s, go to step 7).
  5. Check for poor 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. Check MAF sensor harness for incorrect routing near secondary ignition wires or coils, or other high voltage components such as solenoids, relays or motors. Repair/reroute wiring as necessary. After repairs, go to step 10). If routings are okay, go to next step.
  8. Check for poor connection at MAF signal circuit terminal of VCM. Repair as necessary. After repairs, go to step 10). If connection is okay, go to next step.
  9. Replace VCM. Program replacement VCM using required equipment. After replacing and reprogramming VCM, go to next step.
  10. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0103. Operate vehicle within the 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, repeat step 2).
  11. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
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