P0507 Code: Idle Control System RPM Higher Than Expected

Normal idle speed for a warmed-up engine is 600-800 RPM. P0507 means the ECU has detected that idle speed is consistently higher than expected, typically above 200 RPM over the target. The engine revs higher than it should at rest, wastes fuel, and may cause the car to creep when you shift into drive or release the brake.

This is a common and usually straightforward code. The cause is almost always extra air entering the engine (vacuum leak) or the idle control mechanism not functioning correctly (dirty throttle body or stuck IAC valve).

What causes P0507?

Vacuum leak. The most common cause. Any crack, disconnection, or leak in the intake system introduces unmetered air. The ECU detects the lean condition, adds fuel to compensate, and idle speed rises. Common leak points include the PCV valve hose, brake booster vacuum hose, intake manifold gaskets, and small rubber vacuum lines that crack with age and heat. Dirty throttle body. Carbon deposits accumulate on the throttle blade and bore, reducing the precision of the idle air bypass. The ECU opens the throttle blade wider to maintain idle, which overshoots the target. Cleaning resolves this in about a third of P0507 cases. Faulty idle air control (IAC) valve. On older engines with a separate IAC valve, carbon buildup or electrical failure can cause the valve to stick open, allowing too much air. Cleaning or replacement is the fix. Faulty throttle position sensor (TPS). If the TPS reports the throttle is more closed than it actually is, the ECU miscalculates idle control. The engine idles fast because the ECU thinks it needs to compensate. Coolant temperature sensor reading cold. If the ECT sensor reports a low temperature when the engine is warm, the ECU maintains cold-start fast idle longer than necessary. The sensor is cheap to replace (15-40 euros). Electrical issue with drive-by-wire throttle. On modern vehicles with electronic throttle control, a sticking throttle motor, corroded connector, or damaged wiring can prevent the throttle from closing fully.

Diagnosis

Step 1: Listen for vacuum leaks. With the engine warm and idling, listen for hissing sounds around the intake manifold, vacuum hoses, and PCV system. A can of carb cleaner sprayed carefully around suspected leak points will cause a momentary RPM change if a leak is present (engine speed rises or dips briefly when the cleaner is drawn in). Step 2: Check live data. Monitor idle RPM, coolant temperature, throttle position, and fuel trims. High positive fuel trims (+10% or more) at idle suggest a vacuum leak. Coolant temperature should read 80-100 degrees when warm. Throttle position should read 0-2% at idle. Step 3: Clean the throttle body. Remove the intake boot, spray throttle body cleaner onto the blade and bore, and wipe clean with a rag. Do not force the blade open on drive-by-wire systems. Reassemble and perform an idle relearn if required by your vehicle (some need a specific key-on sequence or scan tool command). Step 4: Inspect the IAC valve (if equipped). Remove, clean with carb cleaner, and check for free movement. Replace if the plunger is stuck.

Skanyx displays idle RPM, throttle position, and fuel trim data side by side in live monitoring, making it easy to spot the telltale signs of a vacuum leak or throttle body issue. skanyx.com/download

Repair costs

Prices estimated as of March 2026.