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Home >> Cadillac >> 2003 >> DeVille DHS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0101: MAF Sensor Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Attempt to start the engine. Does the engine start? If yes, go to next step. If no, go to step  5.
  3. Observe the DTC information with the scan tool. Does the scan tool display any other DTCs except DTC P0101 and P0121? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  4. Observe the Freeze Frame/Failure Records for this DTC. Turn off the ignition for 60 seconds. Start the engine. Operate the vehicle within the Conditions For Running DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
    5. NOTE: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high barometric pressure and/or temperature may cause a reading to be slightly out of range.
  5. Turn ignition on, with engine off. Observe the MAP sensor kPa parameter with a scan tool. The MAP sensor pressure should be within the specified range for your altitude. See Figure. Is the MAP sensor pressure within the specified range as indicated on the Altitude vs. Barometric Pressure table? If yes, go to next step. If no, see DTC P0106: MAP SYSTEM PERFORMANCE .
  6. Start the engine. Turn off all accessories. Allow the engine to reach operating temperature. Observe the MAP SENSOR parameter with a scan tool. Is the MAP SENSOR parameter 0.8-2.2 volts? If yes, go to next step. If no, see DTC P0106: MAP SYSTEM PERFORMANCE .
  7. Idle the engine. Observe the MAP SENSOR parameter with a scan tool. Increase the engine speed slowly to 3000 RPM and then back to idle. Does the MAP SENSOR parameter change smoothly and gradually through the specified range of the test? If yes, go to next step. If no, see DTC P0106: MAP SYSTEM PERFORMANCE .
  8. Turn off the ignition for 30 seconds. Turn ignition on, with engine off. Observe the TP SENSOR parameter at closed throttle with a scan tool. Depress the accelerator pedal completely. Observe the TP SENSOR parameter at Wide Open Throttle (WOT) with a scan tool. Does the TP SENSOR parameter change from 0-100 percent? If yes, go to next step. If no, see DTC P0106: MAP SYSTEM PERFORMANCE .
  9. Turn ignition off. Inspect for the following conditions:
    • A restricted or collapsed air intake duct.
    • A misaligned air intake duct.
    • A dirty or deteriorating air filter element.
    • Any objects blocking the air inlet screen of the MAF sensor.
    • Any contamination or debris on the sensing elements of the MAF sensor.
    • Any water intrusion in the induction system.
    • Any vacuum leak downstream of the MAF sensor.
    • Any type of restriction in the exhaust system.

    Did you find and correct the condition? If yes, go to step  14. If no, go to next step.

  10. Disconnect the MAF/IAT sensor harness connector. Turn ignition on, with engine off. Connect a test light between the ignition 1 voltage circuit of the MAF/IAT sensor and a good ground. Connect a DVOM to the probe of the test light and a good ground. Is voltage less than battery voltage? If yes, go to step  12. If no, go to next step.
  11. Test for an intermittent and/or poor connections at the MAF/IAT sensor. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  12. Repair the high resistance in the MAF/IAT sensor ignition 1 voltage circuit. Did you complete the repair? If yes, go to step  14.
  13. Replace the MAF/IAT sensor. See MASS AIRFLOW/INTAKE AIR TEMPERATURE SENSOR under SENSORS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to next step.
  14. Clear the DTCs with a scan tool. Turn off the ignition for 30 seconds. Start the engine and operate vehicle within the Conditions For Running DTC. You may also operate vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to step  2. If no, go to next step.
  15. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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