P0507 — Idle Air Control System RPM Higher Than Expected

What it means

The idle speed stays above the target, typically by more than 200 rpm, although the idle control has already closed its air path completely. In practice this almost always means unmetered air is entering the intake downstream of the airflow sensor. Symptoms are a permanently raised idle, the car creeping forward with the brake released and delayed rpm drop when lifting off the throttle.

Likely causes (most common first)

1. Vacuum leak at intake manifold gaskets, hoses or the brake booster connection
2. Idle air control valve jammed open or its pintle broken
3. Throttle plate not closing fully because of carbon or a maladjusted stop
4. Leaking or permanently energised purge valve of the evaporative system
5. PCV valve stuck open or a torn crankcase ventilation hose
6. Throttle position sensor signal offset or lost throttle adaptation

Can you drive with it?

You can drive, but braking distances grow and fuel use rises, and a large vacuum leak also leans out the mixture, so fix it soon.