LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2003 >> FX35 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Ignition System >> Ignition Signal >> Ignition Coil & Power Transistor (QX4)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Ignition Coil & Power Transistor (QX4)

  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  12. If engine does not operate, go to step  3.
  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  12.
  3. Let engine idle. Using a voltmeter or CONSULT-II, read voltage between ground and ECM terminals No. 110 and 112. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Battery voltage should exist. If voltage is as specified, go to next step. If voltage is not as specified, see POWER & GROUND CIRCUITS (Q45)  in ENGINE CONTROL MODULE (ECM) under COMPUTERIZED ENGINE CONTROLS.
  4. Turn ignition switch to OFF position. Disconnect condenser harness connector. Turn ignition switch to ON position. Using CONSULT-II or voltmeter, measure voltage between ground and condenser harness connector terminal No. 1. Battery voltage should exist. If voltage is as specified, go to step  10. If voltage is not as specified, go to next step.
  5. Turn ignition switch to OFF position. Disconnect ECM relay. Check for continuity between ECM relay harness connector terminal No. 3 and condenser harness connector terminal No. 1. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check harness for short to power or short to ground. If no problem is found, go to step  7. If problem is found, go to next step.
  6. Check the following:
    • Harness connectors E1, M1, M33 and F22.
    • Check harness for open or short between condenser and ECM relay.

    Repair as necessary. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

  7. Using CONSULT-II or voltmeter, measure voltage between ground and ECM relay harness connector terminal No. 5. Battery voltage should exist. If voltage is as specified, go to step  9. If voltage is not as specified, go to next step.
  8. Check the following:
    • 10-amp fuse.
    • Check harness for open or short between fuse and ECM relay.

    Repair as necessary.

  9. Apply 12 volts to ECM relay terminals No. 1 and 2. See Figure. Check for continuity between ECM relay terminals No. 3 and 5. Also check for continuity between ECM relay terminals No. 6 and 7. Continuity should exist between ecified terminals. Disconnect battery voltage and recheck continuity. Continuity should not exist between indicated terminals. If continuity is as specified, go to step  17. If continuity is not as specified, replace ECM relay.
  10. Turn ignition switch to OFF position. Ensure condenser harness connector is disconnected. Check harness continuity between engine ground and condenser harness connector terminal No. 2. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. 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.
  11. Using ohmmeter, 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.
  12. 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  14. If battery voltage does not exist, go to next step.
  13. Check harness for open or short between ignition coil and harness connector F22. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair or replace harness connectors as necessary. After repair, retest system.
  14. 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. 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.
  15. Disconnect ECM harness connector. Check for continuity between ignition coil harness connector terminal No. 1 and ECM harness connector terminals No. 21, 22, 23, 30, 31 and 32. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check harness for short to ground or short to power. If no problem is found, go to next step. If problem is found, repair harness as necessary.
  16. Using ohmmeter, measure resistance between ignition coil terminals No. 2 and 3. Resistance should be greater than zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace ignition coil and power transistor.
  17. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
scientia non olet · About LEMON Manuals