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Home >> Buick >> 2002 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P0101: MAF Sensor Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Start engine. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool. Does the scan tool display any other DTCs set? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. If yes, see CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Allow the engine to reach operating temperature. Observe the MAP sensor voltage with a scan tool. Is the MAP sensor voltage within 0.8-4 volts? If yes, go to next step. If no, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
  5. Idle the engine. Observe the MAP sensor kPa with a scan tool. Increase the engine speed slowly to 3000 RPM and then back to idle. Does the MAP sensor kPa change smoothly and gradually through the specified range of the test? If yes, go to next step. If no, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
  6. Turn ignition off. Turn ignition on, with engine off. Observe the TP sensor angle from closed throttle to wide open throttle. Depress completely and then release the accelerator pedal. Does the scan tool indicate that the TP sensor angle changed smoothly and completely through the specified range of 0-100 percent? If yes, go to next step. If no, go to DTC P0121: TP SENSOR PERFORMANCE .
  7. Inspect for a restricted air intake duct, collapsed air intake duct, dirty air filter element, or a deteriorating air filter element. Check for any object blocking the air inlet screen of MAF sensor, any debris on the sensing elements of MAF sensor, vacuum leak downstream of MAF sensor, a poor vacuum connection at MAP sensor, a skewed or stuck ECT sensor. Check for high resistance in ground circuit of the ECT sensor or a restricted exhaust system Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
  8. 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  10. If no, go to next step.
  9. Replace the MAF sensor. After replacing sensor, go to next step.
  10. Use the scan tool in order to clear the DTCs. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  11. Using scan tool, observe stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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