1999 Infiniti QX4FACTORY OEM SERVICE PROCEDURE

Idle Air Control Valve-Fast Idle Control Device (IACV-FICD) System Test

  1. Start engine and warm to normal operating temperature. Check idle speed. See SERVICE & ADJUSTMENT SPECIFICATIONS article. Adjust, if necessary. Turn A/C and blower on. If idle speed increases by 50 RPM or more, system is okay. If idle speed does not increase by 50 RPM or more, go to next step.
  2. Check A/C compressor operation. Repair A/C system, if necessary. If A/C compressor operation is okay, check IACV-FICD power and ground circuits. See appropriate diagram in WIRING DIAGRAMS article. Repair as necessary. If circuits are okay, go to next step.
  3. Check ambient air temperature sensor (if equipped). See appropriate AUTOMATIC A/C-HEATER SYSTEMS article. Replace, if necessary. If ambient air temperature sensor is okay, go to next step.
  4. Check IACV-FICD solenoid. See IACV-FICD SOLENOID . Replace, if necessary. If IACV-FICD solenoid is okay, no problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
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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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