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Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0102: Mass Airflow Sensor Circuit - Low Frequency >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Start engine. Using scan tool, observe MAF sensor frequency parameter. If MAF sensor frequency parameter is 1200 Hz, go to step  4. If MAF sensor frequency parameter is not 1200 Hz, 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, then enter this DTC. 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. Turn ignition off. Check fuse in ignition 1 voltage circuit of MAF sensor. Fuse is located in underhood fuse/relay block. If fuse is open, go to step  14. If fuse is okay, go to next step.
  5. Disconnect MAF sensor harness connector. Turn ignition on, with engine off. Check voltage between chassis ground and MAF sensor harness connector terminal "A" (Yellow wire). See Figure. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step  8.
  6. Turn ignition off. Connect a fused jumper wire between ground and MAF harness connector terminal "A" (Yellow wire). Start engine. Recheck for DTCs. If any additional DTCs are set, go to step  16. If no additional DTCs are set, go to next step.
  7. Turn ignition off. Connect a test light between MAF sensor harness connector terminal "C" (Pink wire) and ground circuit. Turn ignition on, with engine off. If test light illuminates, go to step  18. If test light does not illuminate, go to step  11.
  8. If voltage reading is less 4.5 volts, go to step  10. If voltage reading is not less than 4.5 volts, go to next step.
  9. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Check voltage between ground and MAF sensor harness connector terminal "A" (Yellow wire). If voltage reading is zero volts, go to step  12. If voltage reading is not zero volts, go to step  15.
  10. Turn ignition off. Disconnect PCM harness connector. Check for high resistance, open circuit, short to ground, or short to ground circuit on Yellow wire between MAF sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 69. Repair as necessary. After repairs, go to step  22. If circuit is okay, go to step  12.
  11. Connect a test light between MAF sensor harness connector terminal "C"(Pink wire) and a known-good ground. If test light illuminates, go to step  13. If test light does not illuminate, go to step  14.
  12. Turn ignition off. Using a DVOM, check for continuity of Yellow wire between MAF sensor and PCM harness connectors. If continuity exists, go to step  17. If continuity does not exist, go to step  19.
  13. Turn ignition off. Repair high resistance or open in Black/White wire between MAF sensor harness connector terminal "B" and ground connector. After repairs, go to step  22.
  14. Turn ignition off. Check for short to ground or an open in Pink wire between MAF sensor harness connector terminal "C and underhood fuse/relay block. Repair as necessary. Replace fuse, if open. After repairs, go to step  22. If circuit is okay, go to step  20.
  15. Turn ignition off. Repair short to voltage in Yellow wire between MAF sensor and PCM harness connectors. After repairs, go to step  22.
  16. Turn ignition off. Repair short between MAF sensor signal circuit (Yellow wire) and circuit for which the DTC set. After repairs, go to step  22.
  17. Repair circuits that are shorted together. After repairs, go to step  22.
  18. Turn ignition off. Check for poor connections at MAF sensor harness connector. Repair as necessary. After repairs, go to step  22. If connections are okay, go to step  20.
  19. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step  22. If connections are okay, go to step  21.
  20. Replace MAF sensor. After replacing sensor, go to step  22.
  21. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  22. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See CODE ENABLE CRITERIA . If DTC runs and passes, go to next step. If DTC resets, go to step  2.
  23. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, system is okay.
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