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Home >> Cadillac >> 2002 >> Seville STS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.6L >> Diagnostic Tests >> DTC P1106: Map System Performance >> Diagnostic Procedure
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Diagnostic Procedure

  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. Install a scan tool. Start the engine. Monitor the Diagnostic Trouble Code (DTC) Information using the scan tool. Does the scan tool indicate that DTC P0108 or P1635 is current? If yes, see DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE  or DTC P1635: 5-VOLT REFERENCE A CIRCUIT  . If no, go to next step.
  3. Does the scan tool indicate that the MAP sensor voltage is greater than 4.5 V? If yes, go to step  5. If no, go to next step.
  4. With a scan tool observe the MAP sensor voltage, while moving the following components:
    • The MAP sensor connector.
    • The PCM connector.
    • The wiring harness related to the MAP sensor.

    Does the scan tool indicate that the MAP sensor voltage is more than 4.5 V and holding? If yes, go to next step. If no, go to step  13.

  5. Turn OFF the ignition. Disconnect the MAP sensor electrical connector. Turn the ignition ON, with the engine OFF. Does the scan tool indicate that the MAP sensor voltage is less than 0.5 V? If yes, go to next step. If no, go to step  8.
  6. Measure the voltage from the 5-volt reference circuit to the reference low circuit at the MAP sensor electrical connector. Does the voltage measure 4.7-5.2 V? If yes, go to step  11. If no, go to next step.
  7. Does the voltage measure more than 5.2 V? If yes, go to step  10. If no, go to step  9.
  8. Test the signal circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  9. Test the low reference circuit of the MAP sensor for an open. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  10. Test the 5-volt reference circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  11. Inspect for poor connections at the MAP sensor. Did you find and correct the condition? If yes, go to step  13. If no, see DIAGNOSTIC AIDS .
  12. Inspect for poor connections at the PCM. Did you find and correct the condition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  13. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  14. Observe the stored information, Capture Info with a scan tool. 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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