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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 335 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0102: Mass Airflow Sensor Circuit - Low Signal/Frequency >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS .
    2. NOTE: If you were sent here from DTC P0101, proceed to next step.
  2. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 90 seconds. Start engine. Operate vehicle within the Conditions for Running the DTC as specified in the supporting text, or as close to the Freeze Frame/Failure Records that you observed. Did the DTC fail this ignition? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  3. Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor. Is the fuse open? If yes, go to step  10. If no, go to next step.
  4. Turn ignition off. Inspect for a restricted air intake duct, collapsed air intake duct, misaligned air intake duct, dirty air filter element, deteriorating air filter element, objects blocking the air inlet screen of MAF sensor, debris on the air diffuser of MAF sensor, debris or contamination on the sensing element of MAF sensor, vacuum leak downstream of MAF sensor, or any type of restriction in the exhaust system. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  5. Start and idle the engine. Observe the MAF sensor g/s with a scan tool. Move the harness and the connector of the MAF sensor. Does the movement of the harness or the connector affect the MAF sensor g/s? If yes, go to step  15. If no, go to next step.
  6. Turn ignition off. Disconnect the MAF sensor harness connector. Turn ignition on, with engine off. DO NOT use the low reference circuit located in the MAF/IAT connector for this test or ECM damage will result. Connect a test light between the ignition 1 voltage circuit of the MAF sensor and a good ground. Connect the DVOM to the probe of the test light and a good ground. Is the voltage less than battery voltage? If yes, go to step  14. If yes, go to next step.
  7. Measure the voltage from the 5-volt reference circuit of the MAF sensor to a good ground with a DVOM. Is voltage within 4.8-5.2 volts? If yes, go to next step. If no, go to step  9.
  8. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAF sensor and the signal circuit of the MAF sensor. Observe the MAF sensor parameter with a scan tool. Is the MAF sensor parameter more than 4.8 volts? If yes, go to step  16. If no, go to step  11.
  9. Is the voltage less than 5 volts? If yes, go to step  12. If no, go to step  13.
    10. NOTE: The ignition 1 voltage circuit of the MAF sensor is spliced to other components of the vehicle.
  10. Test the ignition 1 voltage circuit of the MAF sensor for a short to ground. Did you find and correct the condition? If yes, go to step  20.
  11. Turn ignition off. Disconnect the ECM. Test the signal circuit of the MAF sensor for a high resistance, open, or short to ground. Did you find and correct the condition? If yes, go to step  20. If no, go to step  17.
    12. NOTE: The 5-volt reference circuit is shared with other components of the vehicle.
  12. Turn ignition off. Disconnect the ECM. Test the 5-volt reference circuit of the MAF sensor for a high resistance, open, short to the low reference of the MAF sensor, or short to ground. Did you find and correct the condition? If yes, go to step  20. If no, go to step  17.
    13. NOTE: The 5-volt reference circuit is shared with other components of the vehicle. A short to voltage on the FTP sensor signal circuit will feed back through the FTP sensor to the FTP 5-volt reference circuit.
  13. Turn ignition off. Disconnect the ECM. Turn ignition on, with engine off. Test the 5-volt reference circuit of the MAF sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  20. If no, go to step  17.
  14. Repair the high resistance or an open in the ignition 1 voltage circuit of the MAF sensor. After repairs, go to step  20.
  15. Repair the harness or the connections as necessary. After repairs, go to step  20.
  16. Test for an intermittent and for a poor connection at the MAF sensor. Did you find and correct the condition? If yes, go to step  20. If no, go to step  18.
  17. Test for an intermittent for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step  20. If no, go to step  19.
  18. Replace MAF/IAT sensor. After replacing sensor, go to step  20.
  19. Replace ECM. Perform ECM relearn procedures. See ENGINE CONTROL MODULE  under PROGRAMMING. After replacing ECM, go to next step.
  20. Clear the DTCs with a scan tool. Turn ignition off for 90 seconds. Start engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  21. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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