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P1502 – Idle Air Control System Underspeed

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Symptoms

  • Low idle
  • Stalling
  • Rough idle

Causes

  • Weak IAC valve
  • Carbon buildup
  • Vacuum leak

Diagnosis

  • Check IAC movement
  • Inspect intake
  • Check vacuum

Repair

  • Clean or replace IAC
  • Repair leaks
  • Clean throttle body
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