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Fuel Pump Control System (Pathfinder & QX4)

  1. Turn ignition on. Pinch fuel hose with fingers. Pulsation should be felt on fuel hose for one second 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 relays No. 1 and 2. See Figure and Fig 1 . Turn ignition on. Measure voltage between ground and terminal No. 2 (Black/Yellow wires) at fuel pump relays No. 1 and 2 harness connectors. See Figure. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  3. Measure voltage between ground and fuel pump relay No. 1 harness connector terminal No. 3 (Black/Red wire). If battery voltage exists, go to step  6. If battery voltage does not exist, go to next step.
  4. Turn ignition off. Check continuity of Black/Red wire between fuel pump relay No. 2 harness connector terminal No. 5 and fuel pump relay No. 1 harness connector terminal No. 3. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  5. Turn ignition on. Measure voltage between ground and fuel pump relay No. 2 harness connector terminals No. 2 (Black/Yellow wire) and No. 3 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  6. Turn ignition off. Check continuity between ground and fuel pump relay No. 2 harness connector terminal No. 1 (Black wire). Continuity should exist. Also, check circuit for short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  7. Turn ignition off. Disconnect fuel pump harness connector located behind access cover, under rear seat. Check continuity between ground and fuel pump harness connector terminal No. 2 (Black wire). Continuity should exist. Also, check circuit for short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  8. Check continuity of White/Blue wire between fuel pump harness connector terminal No. 1 and fuel pump relay No. 1 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.
  9. Disconnect ECM harness connector. See Figure. Check continuity of Red/Blue wire between ECM harness connector terminal No. 28 and fuel pump relay No. 1 harness connector terminal No. 1. 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.
  10. Check both fuel pump relays. See RELAYS & SOLENOIDS . Replace, if necessary. If fuel pump relay is okay, go to next step.
  11. Check fuel pump. See FUEL PUMP . Replace, if necessary. If fuel pump is okay, go to next step.
  12. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article,
Fig 1: Locating Fuel Pump Relay No. 1 (Pathfinder & QX4)
G00051951Courtesy of NISSAN MOTOR CO., U.S.A.
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