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Home >> Infiniti >> 2001 >> QX4 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel System >> Fuel Delivery >> Fuel Pump Control System (Altima)
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Fuel Pump Control System (Altima)

  1. Turn ignition on. Pinch fuel hose with fingers. Pulsation should be felt on fuel hose for 5 seconds after ignition is turned on. If pulsation is felt, system is okay. If pulsation is not felt, go to next step.
  2. Turn ignition off. Remove fuel pump relay from fuse block. Fuse block is located under left side of instrument panel. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (Black/Blue wire) and No. 3 (Black/White wire). See Figure. If battery voltage exists at both terminals, go to next step. If battery voltage does not exist at both terminals, repair open or short circuit. See WIRING DIAGRAMS article.
  3. Turn ignition off. Disconnect fuel pump harness connector located behind access panel, under rear seat. Check continuity between ground and Black wire at fuel pump harness connector. Continuity should exist. Also, check circuit for short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  4. Check continuity of Black/Yellow wire between fuel pump harness connector and fuel pump relay harness connector terminal No. 5. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  5. Disconnect ECM harness connector. See Figure. Check continuity of Black/Pink wire between ECM harness connector terminal No. 6 and fuel pump relay harness connector terminal No. 2. See Figure. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  6. Check fuel pump relay. See RELAYS & SOLENOIDS . Replace, if necessary. If fuel pump relay is okay, go to next step.
  7. Check fuel pump. See FUEL PUMP . Replace, if necessary. If fuel pump is okay, go to next step.
  8. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article,
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