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ENRUDEPLES

P0505 — Idle Air Control System

moderate

What it means

The ECU cannot hold the commanded idle speed within tolerance using the idle air control valve or the electronic throttle. It compares target idle rpm with the actual crankshaft speed and the air mass needed to reach it. Symptoms range from an unstable or hunting idle to stalling when the clutch is pressed, when the air conditioning switches on or during cold starts.

Likely causes (most common first)

  1. Carbon deposits in the throttle body or on the idle air control valve pintle
  2. Sticking or electrically failed idle air control valve
  3. Unmetered air leaking through intake gaskets, vacuum hoses or the brake booster line
  4. Dirty mass airflow sensor or drifting manifold pressure sensor
  5. Throttle position sensor out of adaptation after cleaning or battery disconnection
  6. Broken wiring or driver stage in the ECU controlling the idle valve

Can you drive with it?

Short journeys are possible, but the engine may stall at junctions, so have it fixed soon.

This is the generic meaning. What about your car?

The same code has different typical culprits on different engines. Tell the AI your make, model and year — it will rank the causes for your exact car and give you a check order.

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