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Home >> Pontiac >> 2002 >> Aztek FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P1374: 3X Reference Circuit >> Diagnostic Procedures
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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. Attempt to start the engine. Does the engine start and run? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn OFF the ignition. Disconnect the 6-way ignition control module connector. Remove the injector fuse. Turn ON the ignition, with the engine OFF. Momentarily probe the low resolution engine speed signal circuit at the ignition module harness connector with a test lamp connected to battery voltage. Observe the Engine Speed parameter with a scan tool. Is an Engine Speed displayed? If yes, go to step  8. If no, go to next step.
  5. Did the test lamp illuminate? If yes, go to step  7. If no, go to next step.
  6. Turn OFF the ignition. Disconnect the PCM. Turn ON the ignition, with the engine OFF. Test the low resolution engine speed signal circuit of the ignition control module for an open or a short to voltage. Did you find and correct the condition? If yes, go to step  12. If no, go to step  9.
  7. Turn OFF the ignition. Disconnect the PCM. Test the low resolution engine speed signal circuit of the ignition control module for a short to ground. Did you find and correct the condition? If yes, go to step  12. If no, go to step  9.
  8. Test for an intermittent and for a poor connection at the ignition control module. Did you find and correct the condition? If yes, go to step  12. If no, go to step  10.
  9. Test for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  10. Replace the ignition control module. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  12.
  11. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. 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.
  13. 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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