How to Fix P0507: High Idle RPM Causes and Repair Cost

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 or corroded connector wiring can prevent the throttle from closing fully.

How do you diagnose P0507?

Step 1: Listen for vacuum leaks. With the engine warm and idling, listen for hissing sounds around the intake manifold area, along vacuum hoses, and at the 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 gets drawn in. Step 2: Check live data. Monitor idle RPM, coolant temperature, throttle position, and fuel trims using a live data stream. High positive fuel trims (+10% or more) at idle suggest a vacuum leak - the same lean signature that sets P0171. 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. The process is similar to cleaning the MAF sensor - gentle solvent, no abrasives. 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). Our full throttle body cleaning walkthrough covers the relearn step in detail. Step 4: Inspect the IAC valve (if equipped). Remove, clean with carb cleaner, and check for free movement. Replace if the plunger is stuck.

A 1,200 RPM warm idle that creeps the car forward in drive feels alarming, but P0507 is rarely an emergency. Skanyx reads the code, tells you in about a minute whether it is safe to keep driving or worth parking, then shows idle RPM, throttle position, and fuel trim side by side so the vacuum leak signature (high positive trims at low RPM) or a throttle position mismatch shows up at a glance. skanyx.com/download

How much does it cost to fix P0507?

Prices estimated as of March 2026.

Start with the cheapest fix first: check vacuum hoses, then clean the throttle body. Those two steps resolve P0507 in the majority of cases for under 20 euros and 30 minutes of work. If the high idle persists after both, move to live data - fuel trim readings at idle will point you at the remaining causes before you spend money on parts. A rough idle that accompanies the high RPM is often the same vacuum leak presenting two symptoms at once.