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Home >> Nissan-Datsun >> 2002 >> Sentra SE-R, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing - 4 CYL & V6 >> Fuel System >> Fuel Delivery >> Fuel Pump Control System (Pathfinder & QX4)

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 fuel pump relays No. 1 and 2 harness connector terminal No. 1 (Black/Yellow wires). See Fig 2. If battery voltage does not exist, go to next step. If battery voltage exists, leave relays disconnected and go to step  4.
  3. Check following:
    • Check for poor, loose, corroded or damaged terminal connections in fuse block harness connector M10. See WIRING DIAGRAMS article.
    • Check fuse block fuse No. 17 (15-amp).
    • Check for poor, loose, corroded or damaged terminal connections in in-line harness connectors M1 and E1.
    • Check for open or short in circuits between fuse and fuel pump relays No. 1 and 2.
    If problem is found, repair as necessary. After repair, retest system.
  4. Measure voltage between ground and fuel pump relay No. 1 harness connector terminal No. 3 (Black/Red wire). If battery voltage does not exist, leave relays disconnected and go to next step. If battery voltage exists, leave relays disconnected and go to step  8.
  5. 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. Continuity should exist. Also, check circuit for short to ground and short to voltage. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
  6. Turn ignition on. Measure voltage between ground and fuel pump relay No. 2 harness connector terminals No. 1 (Black/Yellow wire) and No. 3 (Black/White wire). If battery voltage does not exist, go to next step. If battery voltage exists, go to step  8.
  7. Check following:
    • Check fusible link and relay box fuse No. 66 (15-amp).
    • Check for open or short in Black/White wire between fuse and fuel pump relay No. 2. See WIRING DIAGRAMS article.
    If problem is found, repair as necessary. After repair, retest system.
  8. Turn ignition off. Check continuity in Black wire between ground and fuel pump relay No. 2 harness connector terminal No. 1. See Fig 2. Continuity should exist. Also, check circuit for short to voltage. If problem is found, repair as necessary. If no problem is found, go to next step.
  9. Turn ignition off. Disconnect fuel pump harness connector located under access cover, under rear seat. Check continuity between ground and fuel pump harness connector terminal No. 2 (Black wire). Continuity should exist. 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. If problem is found, go to next step. If no problem is found, go to step  11.
  10. Check following:
    • Check for poor, loose, corroded or damaged terminal connections in in-line harness connectors M1 and E1. See WIRING DIAGRAMS article.
    • Check for poor, loose, corroded or damaged terminal connections in in-line harness connectors M2 and B2.
    • Check for open or short in circuits between fuel pump and fuel pump relay.
    If problem is found, repair as necessary. After repair, retest system.
  11. Turn ignition off. Disconnect ECM 116-pin harness connector. For ECM location, see Figure. Check continuity of Purple/Blue wire between ECM harness connector terminal No. 28 and fuel pump relay No. 1 harness connector terminal No. 2. See Figure and Fig 2 . Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If no problem is found, and CONSULT-II is available, go to step  13. If no problem is found, and CONSULT-II is not available, go to step  14.
  12. Check following:
    • Check for poor, loose, corroded or damaged terminal connections in in-line harness connectors M1 and E1. See WIRING DIAGRAMS article.
    • Check for poor, loose, corroded or damaged terminal connections in in-line harness connectors M32 and F23.
    • Check for open or short in circuits between ECM and fuel pump relay No. 1.
    If problem is found, repair as necessary. After repair, retest system.
  13. Connect fuel pump relays and any other disconnected harness connectors. Turn ignition on. Using CONSULT-II in ACTIVE TEST mode, turn fuel pump relays No. 1 and 2 On and Off. Fuel pump relays should click audibly. If fuel pump relays click as specified, go to step  15. If fuel pump relays do not click as specified, replace relay(s).
  14. Working first with fuel pump relay No. 1, apply battery voltage and ground to fuel pump relay terminals No. 1 and 2. See Fig 2. When battery voltage is applied, continuity should exist between terminals No. 3 and 5. When battery voltage is removed, continuity should not exist. Repeat test with fuel pump relay No. 2. Replace suspect relay, if test values are not as specified. If relay tests okay, go to next step.
  15. Check fuel pump. See FUEL PUMP . Replace, if necessary. If fuel pump is okay, go to next step.
  16. 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.
Fig 2: Identifying 4-Pin Relay Harness Connector Terminals
G00015117Courtesy of NISSAN MOTOR CO., U.S.A.
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