P0519 Idle speed control: reading or operation not right

By: Diagno editorial team · Updated: 2026-10-15

P0519 means: Idle speed control: reading or operation not right. The computer holds the idle speed steady with the throttle or an idle valve. OK to drive, but have it checked soon. The most common repair costs about €90–180 in Estonia, depending on make and model.

What it means

The computer holds the idle speed steady with the throttle or an idle valve. The speed is wrong or can't be held steady. There is a signal, but the reading or operation isn't plausible. The cause may be the part itself or a real mechanical fault.

What you may notice

• Idle hunts or is too high or low
• The engine may stall
• Engine light on

What could be wrong

1. 1Dirty throttle body or idle valve · Valve replacement €90–180
2. 2Air leak · Leak check and hose or gasket replacement €60–120
3. 3Throttle needs relearning · Throttle body clean or replace €90–180
4. 4Faulty idle valve · Valve replacement €90–180

Repair difficulty: Easy

What you can check yourself

Cleaning the throttle body often helps. After cleaning or disconnecting the battery, the throttle often has to be relearned. You can do the simpler checks yourself.

How we fix it

1. We clean and relearn the throttle body
2. We check for air leaks
3. We replace the idle valve or throttle body

Standard SAE description: Idle Air Control System Performance