2003 Pontiac Aztek AWDFACTORY OEM SERVICE PROCEDURE

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. Install a scan tool. Start engine. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool. Does the scan tool display DTC P0108 or P1635 set? If yes, see DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE  or DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT  . If no, go to next step.
  3. Observe the MAP sensor parameter with the scan tool. Attempt to induce the fault that set the DTC by manipulating the MAP sensor wiring harness, MAP sensor electrical connector and PCM connector. Is MAP sensor voltage affected during any part of the test? If yes, go to next step. If no, go to step  8.
  4. Test the low reference circuit between the PCM and MAP sensor for an intermittent open or a high resistance. Did you find and correct the condition? If yes, go to step  8. If no, go to next step.
    5. NOTE: Disconnecting the PCM may eliminate the short during testing.
  5. Test the MAP sensor signal circuit between the PCM and MAP sensor for an intermittent short to voltage. Did you find and correct the condition? If yes, go to step  8. If no, go to next step.
  6. Test for an intermittent and for a poor connection at the MAP sensor. Did you find and correct the condition? If yes, go to step  8. If no, go to next step.
  7. Test for an intermittent and for a poor connection at the PCM. Repair as necessary. After repairs, go to next step.
  8. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  9. 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.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.