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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 and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Turn ignition off. Reconnect right bank injector sub-harness connector. Disconnect all right bank injectors and ECM harness connectors. See Figure. Check continuity of the following:
    • Between injector No. 2 harness connector terminal No. 1 (Red/Black wire) and ECM harness connector terminal No. 7 (Light Green wire).
    • Between injector No. 4 harness connector terminal No. 1 (Red/White wire) and ECM harness connector terminal No. 6 (Gray/Blue wire).
    • Between injector No. 6 harness connector terminal No. 1 (Red/Green wire) and ECM harness connector terminal No. 4 (White/Red wire).
    • Between injector No. 8 harness connector terminal No. 1 (Red/Blue wire) and ECM harness connector terminal No. 2 (Red/White wire).
    • Red/Black wire between left bank injector sub-harness connector terminal No. 3 and ECM harness connector terminal No. 1.
    • Red/Blue wire between left bank injector sub-harness connector terminal No. 2 and ECM harness connector terminal No. 14.
    • Purple/Red wire between left bank injector sub-harness connector terminal No. 1 and ECM harness connector terminal No. 5.
    • Red/Yellow wire between left bank injector sub-harness connector terminal No. 6 and ECM harness connector terminal No. 3.

    See Figure. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.

  4. Remove intake manifold collector. See 4.1L - 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 terminal No. 1.
    • Red/White wire between left bank injector sub-harness connector terminal No. 2 and injector No. 3 harness connector terminal No. 1.
    • Red/Green wire between left bank injector sub-harness connector terminal No. 1 and injector No. 5 harness connector terminal No. 1.
    • Red/Blue wire between left bank injector sub-harness connector terminal No. 6 and injector No. 7 harness connector terminal No. 1.

    Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.

  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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