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Home >> GMC >> 2002 >> Jimmy 2D Utility, Part Time, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 385 (Engine Controls - System & Component Testing - 3.4L) >> Ignition Systems >> Electronic Ignition System Diagnosis >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in SELF-DIAGNOSTICS - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. After performing diagnostic system check - engine controls, go to next step.
  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. Disconnect the Crankshaft Position Sensor (CKP) sensor "B" connector from the Ignition Control Module (ICM). Measure the resistance from the CKP sensor "B" CKP sensor 1 signal circuit to the low reference circuit using a DMM. Is the resistance 800-1200 ohms? If yes, go to next step. If no, go to step  28.
  4. Disconnect the CKP "A". Observe the 3X crank sensor parameter using a scan tool. Crank the engine. Does the scan tool indicate a 3X crank sensor signal present? If yes, go to next step. If no, go to step  11.
  5. Reconnect the CKP sensor "A". Test for spark at each cylinder using a Spark Tester (J 26792), or equivalent. Did you observe any non-sparking cylinders? If yes, go to next step. If no, go to step  9.
    6. NOTE: An arching spark plug wire or an arching ignition coil to the ICM may cause a stall or a no start condition.
  6. Check and test the affected cylinder spark plug wires, the ignition coils, and the spark plugs for a short to ground or an arching to ground. If carbon tracking or corrosion is present, replace both components that are affected. Did you find and correct the condition? If yes, go to step  32. If no, go to next step.
  7. Test the spark plug wire resistances. Is the resistance more than 3000 ohms per foot (9868 ohms per meter)? If yes, go to step  30. If no, go to next step.
  8. Measure the ignition coils secondary resistance. Is the resistance 5000-8000 ohms? If yes, go to step  25. If no, go to step  29.
  9. Check the spark plug wires for proper routing and for the correct firing order. If any spark plug wires are found to be misrouted, reroute as necessary. Did you find and correct the condition? If yes, go to step  32. If no, go to next step.
  10. Remove the spark plugs. Inspect spark plugs. Did you find the problem? If yes, go to step  31. If no, go to DIAGNOSTIC AIDS 
  11. Connect the CKP sensor "A". Disconnect the ICM harness connector. Turn ignition switch to RUN position. Connect a test light between the ICM ignition 1 voltage circuit and a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  24.
  12. Connect a test light between the ICM ignition 1 voltage circuit and the ICM ground circuit. Does the test light illuminate? If yes, go to next step. If no, go to step  26.
  13. Test for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step  32. If no, go to next step.
  14. Disconnect the CKP sensor "B" connector from the ICM. Probe the CKP sensor "B" CKP sensor 1 signal circuit using a test light connected to battery voltage. Does the test light illuminate? If yes, go to step  17. If no, go to next step.
  15. Probe the CKP sensor "B" CKP sensor 1 signal circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to step  18. If no, go to next step.
  16. Turn ignition switch to OFF position. Measure the resistance between the CKP sensor 1 signal circuit and the CKP sensor "B" low reference circuit using the DMM at the ICM harness connector. Is the resistance 800-1200 ohms? If yes, go to step  27. If no, go to step  19.
  17. Test the CKP sensor 1 signal circuit for a short to ground. Did you find and correct the condition? If yes, go to step  32. If no, go to step  20.
  18. Test the CKP sensor 1 signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  32. If no, go to step  20.
  19. Test the CKP sensor "B" circuits for the following conditions:
    • An open.
    • The CKP sensor 1 signal and the low reference circuit shorted together.

    Test for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step  32. If no, go to step  20.

  20. Test for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step  32. If no, go to next step.
  21. Test for an intermittent and for a poor connection at the CKP sensor. Did you find and correct the condition? If yes, go to step  32. If no, go to next step.
  22. Remove the CKP sensor. Visually inspect the CKP sensor for the following conditions:
    • Physical Damage.
    • Excessive play or looseness.
    • Improper installation.
    • Foreign material passing between the CKP sensor and the reluctor wheel.
    • Wiring routed too closely to secondary ignition components.

    Did you find and correct the condition? If yes, go to step  32. If no, go to next step.

  23. Visually inspect the reluctor wheel for the following conditions:
    • Foreign material passing between the CKP sensor and the reluctor wheel.
    • Physical Damage.
    • Excessive end play or looseness.
    • Improper installation.
    • Excessive air gap between the CKP sensor and the reluctor wheel.

    Did you find and correct the condition? If yes, go to step  32. If no, go to step  28.

  24. Repair the open or the short to ground in the ICM ignition 1 voltage circuit. Replace the fuse if necessary. After repair, go to step  32.
  25. Remove the coils associated with the cylinder that did not have spark. Connect a test light across the ICM primary circuit, between the ICM terminals for the coils. Observe the test light while cranking the engine. Does the test light flash continuously while the engine is being cranked? If yes, go to step  29. If no, go to step  27.
  26. Repair the open in the ICM ground circuit. After repair, go to step  32.
  27. Replace the ICM. After repair, go to step  32.
  28. Replace the CKP sensor "B". After repair, go to step  32.
  29. Replace the affected ignition coils. After repair, go to step  32.
  30. Replace the spark plug wires. After repair, go to step  32.
  31. Replace the spark plugs. After repair, go to next step.
  32. Turn the ignition switch to OFF position for 30 seconds. Start the engine and operate the vehicle. Observe the MIL, vehicle performance, and driveability. Does the vehicle operate normally, with no MIL? If yes, system is okay at this time. If no, go to step  2.
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