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Home >> Infiniti >> 1999 >> Q45 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel System >> Fuel Control >> Fuel Injector Circuits (Q45)
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Fuel Injector Circuits (Q45)

  1. With engine idling, listen to each injector for operating sound. Each injector should click. If each injector clicks, test is complete. If any injector does not click, go to next step.
  2. Turn ignition off. Disconnect injector sub-harness connectors. See Fig 1 and Fig 2 . Turn ignition on. Measure voltage between ground and right bank injector sub-harness connector terminal No. 4 (White wire). Measure voltage between ground and left bank injector sub-harness connector terminal No. 5 (White wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate diagram in WIRING DIAGRAMS article.
  3. Turn ignition off. Disconnect all right bank injectors and PCM harness connectors. See Figure. Check continuity of the following:
    • Red/Black wire between injector No. 2 harness connector and PCM harness connector terminal No. 7 (Light Green wire).
    • Red/White wire between injector No. 4 harness connector and PCM harness connector terminal No. 6 (Gray/Blue wire).
    • Red/Green wire between injector No. 6 harness connector and PCM harness connector terminal No. 4 (White/Red wire).
    • Red/Blue wire between injector No. 8 harness connector and PCM harness connector terminal No. 2 (Red/White wire).
    • Red/Black wire between right bank injector sub-harness connector terminal No. 3 and PCM harness connector terminal No. 1.
    • Red/Blue wire between right bank injector sub-harness connector terminal No. 2 and PCM harness connector terminal No. 14.
    • Purple/Red wire between right bank injector sub-harness connector terminal No. 1 and PCM harness connector terminal No. 5.
    • Red/Yellow wire between right bank injector sub-harness connector terminal No. 6 and PCM harness connector terminal No. 3.

    See Figure. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.

  4. Remove intake manifold collector. See 4.1L V8 - Q45 article in ENGINES. Disconnect all left bank injector harness connectors. Check continuity between the following:
    • Red/Black wire between left bank injector sub-harness connector terminal No. 3 and injector No. 1 harness connector.
    • Red/White wire between left bank injector sub-harness connector terminal No. 2 and injector No. 3 harness connector.
    • Red/Green wire between left bank injector sub-harness connector terminal No. 1 and injector No. 5 harness connector.
    • Red/Blue wire between left bank injector sub-harness connector terminal No. 6 and injector No. 7 harness connector.

    If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.

  5. Check fuel injector. See FUEL INJECTOR . Replace if necessary. If fuel injector is okay, go to next step.
  6. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
Fig 1: Locating Left Bank Injector Sub-Harness Connector (Q45)
G99I51118Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Locating Right Bank Injector Sub-Harness Connector (Q45)
G99H51083Courtesy of NISSAN MOTOR CO., U.S.A.
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