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Home >> Infiniti >> 2003 >> M45 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Ignition System >> Ignition Signal >> Ignition Coil & Power Transistor (G35)
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Ignition Coil & Power Transistor (G35)

  1. Turn ignition switch to OFF position. Attempt to start engine. If engine operates and CONSULT-II is being used for diagnosis, go to next step. If engine operates and CONSULT-II is not being used for diagnosis, go to step  3. If engine does not operate, go to step  4.
  2. Using CONSULT-II, perform POWER BALANCE in ACTIVE TEST mode. At each step in POWER BALANCE test, engine RPM should drop momentarily. If engine RPM drops as specified, test is complete. If engine RPM does not drop as specified, go to step  10.
  3. Let engine idle. Using an oscilloscope, read voltage between ground and ECM terminals No. 5, 6, 7, 15, 16 and 17. See Figure. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If wave pattern is as illustrated, test is complete. If wave pattern is not as illustrated, go to step  10.
  4. Using voltmeter, check voltage between ground and ECM harness connector terminals No. 110 and 112. Battery voltage should exist. If battery voltage exists, go to next step. If battery voltage does not exist, see POWER & GROUND CIRCUITS (G35)  in ENGINE CONTROL MODULE (ECM) under COMPUTERIZED ENGINE CONTROLS.
  5. Using voltmeter, check voltage between ECM harness connector terminal No. 31 and ground. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Battery voltage should exist. If battery voltage exists, go to step  8. If battery voltage does not exist, go to next step.
  6. Turn ignition switch to OFF position. Disconnect ECM harness connector. Disconnect IPDM E/R harness connector. Check harness continuity between ECM harness connector terminal No. 31 and IPDM E/R harness connector terminal No. 35. Continuity should exist. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Also check harness for short to power or short to ground. If problem is found, go to next step. If no problem is found, replace IPDM E/R.
  7. Check the following:
    • Harness connectors E12 and F3.
    • Check harness for open or short between ECM and IPDM E/R.

    Repair or replace harness or connectors as necessary.

  8. Turn ignition switch to OFF position. Disconnect condenser harness connector. Disconnect ECM harness connector. Check harness continuity between ECM harness connector terminal No. 31 and condenser harness connector terminal No. 1. Continuity should exist. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Also check harness for short to power or short to ground. If no problem is found, go to next step. If problem is found, replace IPDM E/R.
  9. Ensure ignition switch is in OFF position. Ensure condenser harness connector is disconnected. Check harness continuity between ECM harness connector terminal No. 12 and condenser harness connector terminal No. 1. Continuity should exist. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Also check harness for short to power or short to ground. If no problem is found, go to next step. If problem is found, repair short to power or short to ground in harness, or faulty connector.
  10. Turn ignition switch to OFF position. Ensure all disconnected harness connectors are reconnected. Disconnect ignition coil harness connector. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Check voltage between ground and ignition coil harness connector terminal No. 3. If battery voltage exists, go to step  12. If battery voltage does not exist, go to next step.
  11. Check the following:
    • Harness connectors F18 and F201.
    • Check harness for open or short between ignition coil and ECM.
    • Check harness for open or short between ignition coil and harness connector F3.

    Repair or replace harness or connectors as necessary.

  12. Turn ignition switch to OFF position. Check for continuity between ignition coil harness connector terminal No. 2 and engine ground. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check for short to power. If problem is found, go to next step. If no problem is found, go to step  14.
  13. Check the following:
    • Harness connectors F18 and F201.
    • Check harness for open or short to power between ignition coil and engine ground.

    Repair or replace harness or connectors as necessary.

  14. Disconnect ECM harness connector. Check for continuity between ignition coil harness connector terminal No. 1 and ECM harness connector terminals No. 5, 6, 7, 15, 16 and 17. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check for short to ground or short to power. If problem is found, go to next step. If no problem is found, go to step  16.
  15. Check the following:
    • Harness connectors F18 and F201.
    • Check harness for open or short between ignition coil and ECM.

    Repair or replace harness or connectors as necessary.

  16. Disconnect ignition coil harness connectors. Using ohmmeter, measure resistance at specified terminals. See IGNITION COIL WITH POWER TRANSISTOR RESISTANCES  table. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If resistance is as specified, go to next step. If resistance is not as specified, replace ignition coil with power transistor. Recheck system operation.
  17. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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