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Home › Saturn › 2003 › Ion 1 Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0106: Manifold Absolute Pressure System Performance › Diagnostic Procedures

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. Turn ignition on, with engine off. Observe the Throttle Position (TP) sensor voltage with a scan tool. Is the voltage less than 0.90 volt when the throttle is fully closed? If yes, go to next step. If no, go to step  4.
  3. Observe the TP sensor angle with a scan tool. Monitor the scan tool while slowly depressing the accelerator pedal to the floor, then slowly release the pedal. Repeat the procedure several times. Does the TP angle increase steadily when the accelerator pedal is depressed to more than 98 percent and decrease steadily, returning to less than one percent when the pedal is released? If yes, go to step  5. If no, go to step  18.
  4. Inspect the throttle body for binding or damaged linkage, binding or damaged throttle cable, or binding or damaged cruise control cable. Did you find and correct the condition? If yes, go to step  38. If no, go to step  18.
    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 with a scan tool? If yes, go to next step. If no, go to step  7.
  6. Turn ignition on, with engine off. Observe the MAP sensor pressure with a scan tool. Observe the MAP sensor pressure in the known-good vehicle with 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  13.
    7. NOTE: 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 on, with engine off. Observe the MAP sensor pressure with a scan tool. The MAP sensor pressure should be within the range specified for your altitude. Refer to appropriate SENSOR OPERATING RANGE charts. Does the MAP sensor indicate the correct barometric pressure? If yes, go to next step. If no, go to step  13.
  8. Start engine while observing the MAP sensor value with the scan tool. Does the MAP sensor value change while starting the engine? If yes, go to next step. If no, go to step  12.
  9. With the engine running, snap the throttle while observing the MAP sensor value 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  12.
  10. Allow engine to reach operating temperature. Ensure that the transaxle is in Park or Neutral. Turn OFF all of the accessories. Allow engine to idle. Observe the MAP sensor pressure with a scan tool. Is the MAP sensor pressure within 19-42 kPa? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  11. Test for engine vacuum leaks, restricted exhaust, worn piston rings, incorrect cam timing, or for the correct timing. Did you find and correct the condition? If yes, go to step  38. If no, go to step  13.
  12. Turn ignition off. Remove MAP sensor from the vacuum source. Inspect the port for vacuum restrictions or vacuum leaks. Did you find and correct the condition? If yes, go to step  38. If no, go to next step.
  13. Turn ignition off. Disconnect the MAP sensor electrical connector. Turn ON the ignition. Observe the MAP sensor voltage with a scan tool. Is the voltage less than 0.2 volts? If yes, go to next step. If no, go to step  23.
  14. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DVOM. Is the voltage more than 5.2 volts? If yes, go to step  24. If no, go to next step.
  15. Probe the 5-volt reference circuit of the MAP sensor with a test light that is connected to a good ground. Is the test light OFF? If yes, go to step  25. If no, go to next step.
  16. Connect a 3-amp fused jumper wire between the MAP sensor 5-volt reference circuit and the MAP sensor signal circuit. Observe the MAP sensor voltage with a scan tool. Is the voltage more than 4.89 volts? If yes, go to next step. If no, go to step  26.
  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 on, with engine off. Measure the voltage from the low reference circuit of the MAP sensor, at the jumper wire terminal, to a good ground with a DVOM. Is the voltage more than 0.2 volt? If yes, go to step  27. If no, go to step  32.
  18. Turn ignition off. Disconnect the TP sensor. Turn ON the ignition. Observe the TP sensor voltage with a scan tool. Is the voltage less than 0.2 volts? If yes, go to next step. If no, go to step  28.
  19. Measure the voltage from the TP sensor 5-volt reference circuit to a good ground. Is the voltage more than 5.2 volts? If yes, go to step  24. If no, go to next step.
  20. Probe the 5-volt reference circuit of the TP sensor with a test light that is connected to a good ground. Is the test light OFF? If yes, go to step  29. If no, go to next step.
  21. Connect a 3-amp fused jumper between the TP sensor 5-volt reference circuit and the TP sensor signal circuit. Observe the TP sensor with a scan tool. Is the TP sensor voltage more than 4.9 volts? If yes, go to next step. If no, go to step  30.
  22. 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 on, with engine off. Measure the voltage from the low reference circuit of the TP sensor, at the jumper wire terminal, to a good ground with a DVOM. Is the voltage more than 0.2 volt? If yes, go to step  31. If no, go to step  33.
  23. Test the MAP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  38. If no, go to step  37.
  24. Test all of the 5-volt reference circuits for a short to voltage. Did you find and correct the condition? If yes, go to step  38. If no, go to step  37.
  25. Test the 5-volt reference circuit of the MAP sensor for an open or for high resistance. Did you find and correct the condition? If yes, go to step  38. If no, go to step  34.
  26. Test the MAP sensor signal circuit for an open, short to ground, or high resistance. Did you find and correct the condition? If yes, go to step  38. If no, go to step  34.
  27. Test the MAP sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step  38. If no, go to step  34.
  28. Test the TP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  38. If no, go to step  37.
  29. Test the 5-volt reference circuit of the TP sensor for an open or for high resistance. Did you find and correct the condition? If yes, go to step  38. If no, go to step  34.
  30. Test 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  38. If no, go to step  34.
  31. Test the low reference circuit of the TP sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step  38. If no, go to step  34.
  32. Test for poor connections at the MAP sensor. Did you find and correct the condition? If yes, go to step  38. If no, go to step  35.
  33. Test for poor connections at the TP sensor electrical connector. Did you find and correct the condition? If yes, go to step  38. If no, go to step  36.
  34. Test for poor connections at the ECM. Did you find and correct the condition? If yes, go to step  38. If no, go to step  37.
  35. Replace MAP sensor. See MANIFOLD ABSOLUTE PRESSURE SENSOR under SENSORS & SWITCHES in REMOVAL & INSTALLATION - ION article. After replacing sensor, go to step  38.
  36. Replace TP sensor. See THROTTLE POSITION SENSOR under SENSORS & SWITCHES in REMOVAL & INSTALLATION - ION article. After replacing sensor, go to step  38.
  37. Replace ECM. See ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - ION article. Perform ECM relearn procedure. See ENGINE CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After repair, go to next step.
  38. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start 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.
  39. 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.
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