P0518: Idle Air Control Circuit Intermittent
What to do
Driveable. Note when the unstable idle appears — after rain, when hot, or over rough roads — because that pattern points at the connection involved.
What this code means
The idle air control circuit is behaving intermittently. An idle that is stable for days and then hunts for an afternoon usually indicates a connection rather than a valve, and moving the loom by hand with the engine idling is a fast way to provoke it.
Likely causes
Start here
- Corroded or loose connector · easy
- Intermittent open in sensor wiring · moderate
- Faulty idle air control valve · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0518.