1999 Infiniti QX4FACTORY OEM SERVICE PROCEDURE

Power & Ground Circuits (Maxima)

  1. Start engine. If engine starts, go to next step. If engine does not start, turn ignition off and on. Measure voltage between ground and PCM harness connector terminal No. 24 (Red wire) by backprobing. See Figure and Figure . If battery voltage exists, go to step  8. If battery voltage does not exist, repair open or short circuit. See appropriate diagram in WIRING DIAGRAMS article.
  2. Turn ignition off. Measure voltage between ground and PCM harness connector terminal No. 80 (White wire) by backprobing. See Figure. 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. While turning ignition on and off, measure voltage between ground and PCM harness connector terminals No. 67 and 72 (Red wires) by backprobing. Battery voltage should exist for a few seconds after turning ignition off. If voltage is as specified, go to step  8. If battery voltage does not exist, go to next step. If battery voltage exists for more than a few seconds, go to step  7.
  4. Disconnect PCM harness connector. Remove ECCS relay. See Fig 1. Check continuity of Red wires between ECCS relay harness connector terminal No. 5 and PCM harness connector terminals No. 67 and 72. See Figure and Fig 2 . If continuity exists, go to next step. If continuity does not exist, repair open in Red wire(s).
  5. Measure voltage between ground and ECCS relay harness connector terminals No. 2 and 3 (White/Blue wires). 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.
  6. Check continuity of White/Blue wire between ECCS relay harness connector terminal No. 1 and PCM harness connector terminal No. 4. See Figure and Fig 2 . If continuity exists, go to next step. If continuity does not exist, repair open in White/Blue wire.
  7. Check ECCS relay. See RELAYS  under RELAYS & SOLENOIDS. Replace, if necessary and retest system. If relay is okay, go to next step.
  8. Turn ignition off. Loosen and retighten engine ground bolts, located on intake manifold near fuel injectors. Disconnect PCM harness connector. Check continuity between ground and PCM harness connector terminals No. 10, 19, 25, 32, 108, 116 and 124. If continuity exists, go to next step. If continuity does not exist, repair open ground circuit(s).
  9. Check PCM harness connector terminals for damage or corrosion. Repair as necessary, reconnect all connectors and retest system.
Fig 1: Locating ECCS Relay (Maxima)
G99A51110Courtesy of NISSAN MOTOR CO., U.S.A.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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