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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 250 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0105: Manifold Absolute Pressure Sensor Performance/Range >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  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. Connect scan tool. Turn ignition switch to RUN position, engine off. Observe the TP sensor voltage on the scan tool. Does the scan tool display a TP voltage less than 0.9 volt when throttle is fully closed? If yes, go to next step. If no, go to step  4.
  3. Select TP angle parameter on the scan tool. Monitor scan tool while slowly depressing accelerator pedal to the floor, then slowly release pedal. Repeat the procedure several times. Does the TP angle value increase steadily when accelerator pedal is depressed to more than 98 percent value and decrease steadily, returning to less than one percent value when pedal is released? If yes, go to step  5. If no, go to step  22.
  4. Check throttle body for binding linkage or damaged linkage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  22.
    5. NOTE: The vehicle used for the comparison is not limited to the same type of vehicle as is being serviced. A vehicle known to provide an accurate reading is acceptable.
  5. Do you have access to another vehicle in which the MAP sensor pressure can be observed using a scan tool? If yes, go to next step. If no, go to step  7.
  6. Turn ignition switch to RUN position, engine OFF. Observe the MAP sensor pressure using a scan tool. Observe the MAP sensor pressure in the known good vehicle using a scan tool. Compare the values. Is the difference between the values less than 3 kPa? If yes, go to step  8. If no, go to step  12.
    7. 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 pressure and/or very low or very high temperature may cause a reading to be slightly out of range.
  7. Turn ignition switch to RUN position, engine OFF. Observe the MAP sensor pressure using a scan tool. See ALTITUDE VS. BAROMETRIC PRESSURE  table. The MAP sensor pressure should be within the range specified for your altitude. Does the MAP sensor indicate the correct barometric pressure? If yes, go to next step. If no, go to step  12.
  8. Start the engine while watching the MAP sensor value using the scan tool. Does the MAP sensor value change while starting the engine? If yes, go to next step. If no, go to step  11.
  9. With the engine running, snap the throttle while watching the MAP sensor display on the scan tool. Does the MAP sensor value change rapidly when the throttle position changes? If yes, go to next step. If no, go to step  11.
  10. Allow the engine to reach operating temperature. Ensure that the transaxle is in Park (A/T) or Neutral (M/T). Turn all accessories OFF. Allow engine to idle. Observe the MAP sensor pressure using a scan tool. Is the MAP sensor pressure 19-39 kPa? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  11. Turn ignition switch to OFF position. Remove the MAP sensor from the vacuum source. Inspect the port for vacuum restrictions and vacuum leaks. Did you find and correct the condition? If yes, go to step  41. If no, go to next step.
  12. Turn ignition switch to OFF position. Disconnect the MAP sensor harness connector. Turn ignition switch to RUN position. Observe the MAP sensor voltage on the scan tool. Does the scan tool indicate that the voltage is near zero volt? If yes, go to next step. If no, go to step  16.
  13. Measure the voltage between the 5-volt reference circuit of the MAP sensor and a good ground using a DMM. Is the voltage more than 5.2 volts? If yes, go to step  18. If no, go to next step.
  14. Connect a test light to a good ground. Probe the 5-volt reference circuit of the MAP sensor using the test light. Does the test light illuminate? If yes, go to next step. If no, go to step  19.
  15. Connect a 3-amp fused jumper to the MAP sensor 5-volt reference circuit. Connect the other end of the 3-amp fused jumper to the MAP sensor signal circuit. Does the scan tool indicate that the MAP sensor voltage is near 5 volts? If yes, go to step  17. If no, go to step  20.
  16. Check the MAP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  17. Remove the jumper wire. Connect a jumper wire between each of the terminals in the MAP sensor harness connector and the corresponding terminal at the MAP sensor. Turn ignition switch to RUN position, engine OFF. Measure the voltage from the low reference circuit of the MAP sensor, at the jumper wire terminal, to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step  21. If no, go to step  35.
  18. Check all of the 5-volt reference circuits for a short to voltage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  19. Check the 5-volt reference circuit of the MAP sensor for an open, high resistance or a short to ground. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  20. Check the MAP sensor signal circuit for an open, a short to ground or high resistance. Did you find and correct the condition? If yes, go to step  41. If no, go to step  37.
  21. Check the MAP sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step  41. If no, go to step  37.
  22. Turn ignition switch to OFF position. Disconnect the TP sensor harness connector. Turn ignition switch to RUN position, engine off. Observe the TP sensor voltage on the scan tool. Does the scan tool indicate that the TP sensor voltage is near zero volt? If yes, go to next step. If no, go to step  26.
  23. Connect a test light to a good ground. Probe the 5-volt reference circuit of the TP sensor. Does the test light illuminate? If yes, go to next step. If no, go to step  28.
  24. Measure the voltage between the TP sensor 5-volt reference circuit and a good ground. Does the voltage measure more than 5.2 volts? If yes, go to step  31. If no, go to next step.
  25. Connect a 3-amp fused jumper between the TP sensor 5-volt reference circuit and the TP sensor signal circuit. Does the scan tool indicate the TP sensor voltage is near 5 volts? If yes, go to step  27. If no, go to step  32.
  26. Check the TP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  27. Remove the jumper wire. Connect a jumper wire between each of the terminals in the TP sensor harness connector and the corresponding terminal at the TP sensor. Turn ignition switch to RUN position, engine OFF. Measure the voltage from the low reference circuit of the TP sensor, at the jumper wire terminal, to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step  33. If no, go to step  36.
  28. Check the 5-volt reference circuit of the TP sensor for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step  41. If no, go to next step.
  29. Check all of the branches of the 5-volt reference circuits that are shared with the TP sensor for a short to ground. Did you find and correct the condition? If yes, go to step  41. If no, go to step  30.
  30. Measure the voltage from the 5-volt reference circuit of the TP sensor to the low reference circuit of the TP sensor. Disconnect all of the other sensors that share the 5-volt reference circuit with the TP sensor, one at a time. A change in voltage indicates the faulty component. Replace that component as necessary. Did you find and correct the condition? If yes, go to step  41. If no, go to step  34.
  31. Check the 5-volt reference circuit of the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  37.
  32. Check the TP sensor signal circuit for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step  41. If no, go to step  37.
  33. The TP sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step  41. If no, go to step  37.
  34. Check all of the 5-volt reference circuits that are shared with the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  35. Inspect for poor connections at the MAP sensor. Did you find and correct the condition? If yes, go to step  41. If no, go to step  38.
  36. Inspect for poor connections at the TP sensor harness connector. Did you find and correct the condition? If yes, go to step  41. If no, go to step  39.
  37. Inspect for poor connections at the PCM. Did you find and correct the condition? If yes, go to step  41. If no, go to step  40.
  38. Replace the MAP sensor. After repair, go to step  41.
  39. Replace the TP sensor. After repair, go to step  41.
  40. Replace the PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After repair, go to step  42.
  41. Use the scan tool to perform the Fuel Trim Reset procedure. Did you complete the procedure? If yes, go to next step.
  42. Clear the DTCs using scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See 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? If yes, go to step  2. If no, go to next step.
  43. Observe the CAPTURE INFO using the scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
(1) ALTITUDE VS. BAROMETRIC PRESSURE

Altitude - Meters Altitude - Feet Barometric Pressure - kPa
4267 14000 56-64
3962 13000 58-66
3658 12000 61-69
3353 11000 64-72
3048 10000 66-74
2743 9000 69-77
2438 8000 71-79
2134 7000 74-82
1829 6000 77-85
1524 5000 80-88
1219 4000 83-91
914 3000 87-95
610 2000 90-98
305 1000 94-102
0 0 (Sea Level) 96-104
-305 -1000 101-105
(1) Determine your altitude by contacting a local weather station or by using another reference source.
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