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Home >> Infiniti >> 2003 >> M45 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Air Induction Systems >> Variable Induction Air Control System >> Diagnostic Procedure (QX4)
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Diagnostic Procedure (QX4)

  1. Check overall function. Start engine and warm it up to normal operating temperature, and proceed accordingly:
    • With CONSULT-II  - Perform VIAS SOL VALVE in ACTIVE TEST mode. Turn VIAS control solenoid valve on and off, and ensure that power valve actuator rod moves. See Figure. If power valve actuator rod moves, inspection is complete. If power valve actuator rod does not move, go to next step.
    • Without CONSULT-II  - Quickly rev engine to 5,000 RPM and then let engine return to idle. Ensure that power valve actuator rod moves. See Figure. If power valve actuator rod moves, inspection is complete. If power valve actuator rod does not move, go to next step.
  2. Stop engine and disconnect vacuum hose connected to power valve actuator. Check vacuum existence, and proceed accordingly:
    • With CONSULT-II  - Perform VIAS SOL VALVE in ACTIVE TEST mode with CONSULT-II. Turn VIAS control solenoid valve ON and OFF, and check vacuum existence under the following conditions. If VIAS SOL VALVE is ON, vacuum should exist. If VIAS SOL VALVE is OFF, vacuum should not exist. If results are as specified, repair or replace power valve actuator. If results are not as specified, go to next step.
    • Without CONSULT-II  -Disconnect VIAS control solenoid valve harness connector. Start engine and let it idle. Apply 12 volts between VIAS control solenoid valve terminals No. 1 and 2. See Figure. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Check vacuum existence under the following conditions. If 12 volts is applied, vacuum should exist. If no voltage is applied, vacuum should not exist. If results are not as specified, repair or replace power valve actuator. If results are as specified, go to next step.
  3. Stop engine, check hoses and tubes between intake manifold and power valve actuator for cracks, clogging, improper connection or disconnection. If no problem is found, go to next step. If problem is found, repair as necessary.
  4. Disconnect vacuums hoses from vacuum tank. Using vacuum pump, apply vacuum to tank port "A". Attach vacuum gauge to port "B" and ensure that vacuum is maintained. If vacuum is not maintained, replace vacuum tank. If vacuum is maintained, go to next step.
  5. Turn ignition switch to OFF position. Disconnect VIAS control solenoid valve harness connector. Turn ignition switch to ON position. Check voltage between terminal No. 1 and ground with CONSULT-II or tester. See Figure. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Battery voltage should exist. If voltage is as specified, go to step  7. If voltage is not as specified, go to next step.
  6. Check the following:
    • Harness connectors M32 and F23.
    • Fuse (J/B) connector M10.
    • 10-amp fuse.
    • Harness continuity between fuse and VIAS control solenoid valve.

    Repair harness or connectorsas necessary.

  7. Turn ignition switch to OFF position. Disconnect ECM harness connector. Check harness continuity between ECM terminal No. 16 and terminal No. 2. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check harness for short to ground and short to power. If problem is found, repair circuits or connectors as necessary. If problem is not found, 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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