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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 (G20)
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Fuel Injector Circuits (G20)

  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 harness connectors. Turn ignition on. Measure voltage between ground and each injector harness connector Black/Red 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 PCM harness connector. See Figure. Check continuity of the following wires:
    • Red/Black wire between injector No. 1 harness connector and PCM harness connector terminal No. 102.
    • Yellow/Black wire between injector No. 2 harness connector and PCM harness connector terminal No. 107.
    • Green/Black wire between injector No. 3 harness connector and PCM harness connector terminal No. 104.
    • Blue/Black wire between injector No. 4 harness connector and PCM harness connector terminal No. 109.

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

  4. Check fuel injector. See FUEL INJECTOR . Replace if necessary. If fuel injector is okay, go to next step.
  5. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
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