P0509moderate severityPowertrain

Idle Air Control System Circuit High

on 2002 Infiniti QX4 3.5L V6 · RWD

What this code means

High voltage in IAC circuit.

Symptoms

  • High idle
  • Racing idle

Common causes

  • Short to power
  • Faulty IAC motor
  • Open ground

Diagnostic steps

  1. Test IAC voltage
  2. Check for shorts to power

Repair notes

Replace IAC or repair wiring.

Other Powertrain codes on this vehicle

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