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Powertrain fault code

P0506: Idle Air Control System RPM Lower Than Expected

Monitor

Usually drivable, but the engine may stall at idle.

What P0506 means

The engine's idle speed is not where the computer expects it.

Common causes

  • Dirty throttle body or idle valve
  • Vacuum leak
  • Faulty idle control valve

What to check first

  1. Clean the throttle body.
  2. Check for vacuum leaks.

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Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

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Related codes

P0505P0507

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.