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Home >> Chevrolet >> 2002 >> Camaro Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P1374: 3X Reference Circuit >> Diagnostic Procedures

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 continue to run? If yes, go to next step. If no, see ENGINE CRANKS BUT DOES NOT RUN in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Turn OFF the ignition. Disconnect the ignition control module connector. Install a Injector Test Lamp (J 34730-405) at any injector harness connector. Turn ON the ignition, with the engine OFF. Connect a test lamp to battery voltage. Repeatedly touch the test lamp quickly to the low resolution engine speed signal circuit at the ignition control module harness connector while observing the J 34730-405. Does the injector test lamp blink? If yes, go to step  8. If no, go to next step.
  5. Turn OFF the ignition. Disconnect the Powertrain Control Module (PCM). Turn ON the ignition, with the engine OFF. Inspect for the following conditions:
    • Low resolution engine speed signal circuit open
    • Low resolution engine speed signal circuit shorted to ground
    • Low resolution engine speed signal circuit shorted to voltage

    If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to next step.

  6. Inspect the low resolution engine speed signal circuit for a poor terminal connection at the PCM. If a problem is found, replace loose terminal. Did you find and correct the condition? If yes, go to step  11. If no, go to next step.
  7. Inspect for the following conditions:
    • Incorrect harness routing near secondary ignition components.
    • Ignition coil arcing to the wiring harness or to the ignition control module.
      • NOTE: If carbon tracking is detected on any component, replace that component and its mate.
    • Ignition coils for cracks, carbon tracking, or other signs of damage.
    • Secondary ignition wires arcing to the wiring harness.

    If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to step  10.

  8. Inspect for loose terminal connections at the Ignition Control Module (ICM). If a condition is found, replace loose terminals as necessary. Did you find and correct the condition? If yes, go to step  11. If no, go to next step.
  9. Replace the ICM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  11.
  10. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  11. Clear the DTCs with a scan tool. Turn OFF the ignition. 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.
  12. 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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