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Power & Ground Circuits (Pathfinder & QX4)

  1. Start engine. If engine starts, go to step  5. If engine does not start, turn ignition off and on. Measure voltage between ground and ECM terminal No. 43 (Red wire) by backprobing. See Figure and Figure . If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  2. Turn ignition off. Disconnect ECM harness connector. Check continuity between ground and ECM harness connector terminals No. 48, 57, 106 and 108 (Black wires). Continuity should exist. Also, check circuits for short to voltage. Repair circuit(s) as necessary. If all circuits are okay, go to next step.
  3. Remove ECM relay. See Fig 1. Measure voltage between ground and ECM relay harness connector terminals No. 1 (White/Red wire) and No. 5 (Red/White wire). 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.
  4. Check continuity of Blue/Black wire between ECM relay harness connector terminal No. 2 and ECM harness connector terminal No. 26. 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 off. Measure voltage between ground and ECM terminal No. 67 (White/Red wire) by backprobing. See Figure and Figure . If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  6. While turning ignition on and off, measure voltage between ground and ECM terminals No. 110 and 112 (Black/White wires) by backprobing. Battery voltage should exist for a few seconds after turning ignition off, then drop to about zero volts. If voltage is as specified, go to step  11. If battery voltage does not exist, go to next step. If battery voltage exists for more than a few seconds, go to step  8.
  7. Remove ECM relay. See Fig 1. Measure voltage between ground and ECM relay harness connector terminal No. 7 (White/Red wire). 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.
  8. Turn ignition off then on. Measure voltage between ground and ECM terminal No. 12 (White/Red wire) by backprobing. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  9. Turn ignition off. Remove ECM relay. See Fig 1. Check continuity of Black/White wire between ECM relay harness connector terminal No. 6 and ECM harness connector terminals No. 110 and 112. See Figure and 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 ECM relay. See RELAYS & SOLENOIDS . Replace, if necessary. If ECM relay is okay, go to next step.
  11. Turn ignition off. Disconnect ECM harness connector. Check continuity between ground and ECM harness connector terminals No. 48, 57, 106 and 108 (Black wires). Continuity should exist. Also, check circuits for short to voltage. Repair circuit(s) as necessary. If all circuits are 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 ECM Relay, Fuel Pump Relay No. 2 & Fuel Pump Fuse (Pathfinder & QX4)
G00051950Courtesy of NISSAN MOTOR CO., U.S.A.
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