LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2003 >> Q45 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel Systems >> Fuel Control >> Fuel Injector Circuits (Q45)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fuel Injector Circuits (Q45)

  1. Start engine. If engine starts, go to next step. If engine does not start, go to step  5.
  2. If using CONSULT-II, go to next step. If not using CONSULT-II, go to step  4.
  3. Perform POWER BALANCE in ACTIVE TEST mode. If each circuit produces a momentary engine speed drop, system is okay. If any circuit does not produce a momentary engine speed drop, go to step  5.
  4. With engine idling, listen to each injector for operating sound. Each injector should click. If every injector clicks, system is okay. If any injector does not click, go to next step.
  5. Turn ignition switch to OFF position. Disconnect Green 6-pin injector sub-harness connector F21 (for left bank) or F41 (for right bank). Measure voltage between ground and connector F21 or F41 terminal No. 5 (White/Green wire). See Fig 1. If battery voltage exists, go to step  7. If battery voltage does not exist, go to next step.
  6. Check the following:
    • Harness connectors E32 and F32.
    • Harness connectors F21 and F201.
    • Harness connectors F21 and F221.
    • Joint connector-19.
    • Fuse block (J/B) No. 1 connector M1. See Figure.
    • Fuse block (J/B) No. 2 connectors M143 and E215. See Figure.
    • 15-amp fuse.
    • Harness for open or short between harness connector F21 and fuse.
    • Harness for open or short between harness connector F41 and fuse.

    Repair as necessary.

  7. Disconnect ECM harness connector. Check continuity of appropriate wire between connector F21 or F41 and appropriate ECM harness connector terminal. See FUEL INJECTOR CIRCUIT IDENTIFICATION (Q45) table. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also, check circuit for short to ground and short to voltage. If problem is found, repair as necessary. If no problem is found, go to next step.
  8. Check fuel injector. See FUEL INJECTOR . If injector is okay, go to next step. If injector is not okay, replace fuel injector.
  9. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Identifying Fuel Injector Sub-Harness Connector Terminals (Q45)
G98D01317Courtesy of NISSAN MOTOR CO., U.S.A.
FUEL INJECTOR CIRCUIT IDENTIFICATION (Q45)

Sub-Harness Connector Terminal No. (1) Wire Color ECM Harness Connector Terminal No. Injector No.
Connector F21 (Left Bank)
1 Orange/Blue 14 5
2 Brown 7 3
3 Black/White 5 1
6 Orange 16 7
Connector F41 (Right Bank)
1 Black/Red 15 6
2 Pink 13 4
3 Blue 6 2
6 Green 17 8
(1) See Fig 1.
scientia non olet · About LEMON Manuals