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P1509 – Idle Air Control System High Load

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Symptoms

  • Rough idle
  • Hesitation
  • High idle

Causes

  • Vacuum leak
  • Throttle body issue
  • Weak IAC valve

Diagnosis

  • Check vacuum lines
  • Inspect throttle body
  • Test IAC valve

Repair

  • Repair leaks
  • Clean throttle body
  • Replace IAC valve
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