P0507: Idle Air Control System RPM Higher Than Expected
What to do
Expect a fast idle that will not settle — often noticeably high when stopping. Ask for a smoke test for vacuum leaks before any part is replaced; on this code specifically, a new idle valve is very unlikely to be the answer.
What this code means
Idle speed is above target with the module already commanding the minimum air it can. The control has run out of authority in the closing direction, and that points almost entirely one way: air is entering the engine that the idle control did not admit.
This is the single most useful diagnostic in the idle-control family, because it converts a vague idle complaint into a specific search for unmetered air. A split intake hose, a perished vacuum line, a failed PCV diaphragm, a leaking intake manifold gasket or a purge valve stuck open will all do it. A smoke test finds them in minutes.
Replacing the idle air control valve for this code is the classic wasted repair. The valve is already closed.
Likely causes
Start here
- Vacuum leak in intake manifold or hoses · moderate
- Split or disconnected intake boot · easy
- Failed PCV valve or hose · easy
- Leaking intake manifold gasket · moderate
Less common
- Faulty EVAP purge valve · easy
- Binding throttle plate or linkage · 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
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