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Home >> Infiniti >> 2003 >> FX35 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Ignition System >> Ignition Signal >> Ignition Coil & Power Transistor (M45)
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Ignition Coil & Power Transistor (M45)

  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  11.
  3. Let engine idle. Using an oscilloscope, read voltage between ground and ECM terminals No. 18, 19, 20, 21, 29, 30, 31 and 32. See Fig 1. If wave pattern is as illustrated, test is complete. If wave pattern is not as illustrated, go to step  11.
    Fig 1: Identifying Ignition Signal Wave (FX35, FX45, M45 & Q45)
    G00221707Courtesy of NISSAN MOTOR CO., U.S.A.
  4. Using voltmeter, check voltage between ground and ECM harness connector terminals No. 163 and 166. Battery voltage should exist. If battery voltage exists, go to next step. If battery voltage does not exist, see POWER & GROUND CIRCUITS (M45)  in ENGINE CONTROL MODULE (ECM) under COMPUTERIZED ENGINE CONTROLS.
  5. Using voltmeter, check voltage between ECM harness connector terminal No. 12 and ground. Battery voltage should exist. If battery voltage exists, go to step  11. If battery voltage does not exist, go to next step.
  6. Turn ignition switch to OFF position. Disconnect ECM harness connector. Disconnect ECM relay. Check harness continuity between ECM harness connector terminal No. 12 and ECM relay harness connector terminal No. 3. 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 step  8. If problem is found, go to next step.
  7. Check the following:
    • Harness connectors M145 and F105.
    • Fuse block (J/B) No. 2 harness connector M143.
    • Check for open or short between ECM and ECM relay.

    Repair as necessary.

  8. Check voltage between ground and ECM harness connector terminal No. 5. Battery voltage should exist. If battery voltage exists, go to step  10. If battery voltage does not exist, go to next step.
  9. Check the following:
    • 20-amp fuse.
    • Fusible link and relay block (J/B) harness connector E3.
    • Fuse block (J/B) No. 2 harness connector E215.
    • Check for open or short between fuse and ECM relay.

    Repair as necessary.

  10. Check ECM relay. See ECM RELAY  under RELAYS in RELAYS & SOLENOIDS. If ECM relay is okay, go to step  18. If relay is faulty, replace ECM relay.
  11. Turn ignition switch to OFF position. Disconnect condenser harness connector. 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 open circuit or short to power in harness or connectors.
  12. Ensure condenser harness connector is disconnected. Measure resistance between condenser terminals No. 1 and 2. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Resistance should be one megohm at 77°F (25°C). If resistance is as specified, go to next step. If resistance is not as specified, replace condenser.
  13. 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  15. If battery voltage does not exist, go to next step.
  14. Check for open or short circuit between ignition coil and harness connector F105. Repair or replace harness or connector as necessary.
  15. Turn ignition switch to OFF position. Disconnect ignition coil harness connector. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Check continuity between engine ground and ignition coil harness connector terminal No. 2. Continuity should exist. Also check for short to power. If problem is found, repair harness or connectors as necessary. If no problem is found, go to next step.
  16. Disconnect ECM harness connector. Check harness continuity between ignition coil harness connector terminal No. 1 and ECM harness connector terminals No. 18, 19, 20, 21, 29, 30, 30 and 31. Continuity should exist. Also check harness for open, short to ground or short to power. If problem is found, repair harness or connectors as necessary. If no problem is found, go to next step.
  17. 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.
    IGNITION COIL WITH POWER TRANSISTOR RESISTANCES

    Terminal No. Resistance @ 77°F (25°C)
    1 & 2 Except Zero Ohms Or Infinity
    1 & 3 Except Zero Ohms
    2 & 3 Except Zero Ohms
  18. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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