fault code guide
P0507: Idle Control System RPM Higher Than Expected
Your engine is revving faster than normal when parked or idling. The car remains drivable, but it will use extra fuel and may feel awkward to hold on the brakes.
How it shows up: The engine management light stays steadily illuminated on your dashboard, and an OBD scanner will show code P0507. You will notice the rev counter sitting unusually high, often above 1,000 RPM, when stopped at junctions.
Updated 9 November 2026
Can I keep driving?
Service soon
The car is drivable, but an engine idling too fast wears your brakes, burns more fuel, and indicates unmetered air entering the engine.
What to do right now
- 1Check that your accelerator pedal is not caught under a floor mat.
- 2Allow the engine to reach normal operating temperature to see if the high idle settles down.
- 3Firmly apply the handbrake and keep extra distance in traffic, as an automatic gearbox may pull forward harder than usual.
Likely causes
Most likely first.
- Likely
Vacuum leak
A split rubber vacuum hose or leaking intake manifold gasket allows extra unmetered air into the cylinders. The engine computer adds fuel to balance the air, forcing the idle speed upwards.
- Likely
Dirty or sticking throttle body
Oily carbon build-up around the throttle butterfly flap prevents it from shutting completely. Extra air slips through the gap, keeping the idle revs higher than targeted.
- Possible
Faulty positive crankcase ventilation (PCV) valve
If the internal PCV valve spring fails or sticks wide open, it draws excess crankcase fumes and air into the intake tract. This acts just like a large vacuum leak.
- Possible
Defective idle air control valve
On cars using a dedicated idle air control valve rather than an electronic throttle, carbon deposits can jam the valve plunger open. This locks the idle airflow at an elevated rate.
- Rare
Uncalibrated electronic throttle body
Disconnecting the 12-volt battery or cleaning the intake without completing an electronic throttle relearn can leave the computer confused about the true closed flap position.
What you can check yourself
Park somewhere safe and level, engine off, before you start.
- 1
Check the accelerator pedal and floor mat
Park safely and turn off the engine. Inspect the driver footwell to confirm the floor mat has not bunched up behind or over the accelerator pedal.
- 2
Listen for intake hissing
Pop the bonnet, start the engine, and leave it idling in neutral or park with the handbrake firmly applied. Listen around the plastic engine intake manifold for a distinct sucking or hissing sound that points to a split rubber hose.
- 3
Inspect visible vacuum and breather hoses
Turn the engine off and let it cool. Carefully feel and inspect rubber hoses running to the intake manifold for splits, perish cracks, or disconnected ends.
- 4
Perform an electronic throttle reset
Check your owner's handbook for the manual throttle relearn sequence. On many cars, leaving the ignition on without starting the engine for several minutes allows the computer to recalibrate the closed throttle position.
Rough cost to fix
Rough estimateTypical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. Prices depend mainly on whether the fault is cured by a quick clean and hose repair or requires dismantling the intake manifold to renew leaking gaskets.
Throttle body clean and electronic relearn
- Do it yourself
- €10–25£8–20 in the UK
- At a garage
- €80–160£70–140 in the UK
Vacuum hose or PCV valve replacement
- Do it yourself
- €20–70£15–60 in the UK
- At a garage
- €90–200£80–170 in the UK
Intake manifold gasket replacement
- Do it yourself
- Garage job
- At a garage
- €180–380£150–330 in the UK
Electronic throttle body replacement
- Do it yourself
- €120–320£100–280 in the UK
- At a garage
- €240–480£200–420 in the UK
When to go to a garage
- The engine idle revs surge erratically up and down between high and low without touching the accelerator.
- The car surges forward persistently against your foot on the brake pedal at junctions.
- Cleaning the throttle body and checking visible vacuum lines fails to lower the idle speed.
- The engine management light begins flashing, which signals an active engine misfire.
Questions drivers ask
Can I drive my car with fault code P0507?
Yes, you can usually drive home or to a garage safely. Keep in mind that in an automatic car, the transmission will pull harder against the brakes when stopped in gear, so allow extra braking distance.
Will clearing code P0507 make it go away?
No, simply deleting the fault code with an OBD scanner will not solve the underlying problem. As soon as the engine reaches operating temperature and idles above factory thresholds again, the computer will trigger the light once more.
Will fault code P0507 cause an MOT or NCT failure?
In the UK, a lit engine management light is an automatic MOT failure on petrol cars registered from July 2003 and diesels from July 2008. In Ireland, the engine light alone results in an Advisory Pass at the NCT, but the car will fail if the high idle pushes exhaust emissions past legal limits.
Why does my engine idle high only when cold?
Engines are programmed to idle higher for the first few minutes after a cold start to warm up the catalytic converter and oil. Code P0507 is only logged when the engine continues to rev abnormally high after it has reached full operating temperature.
Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.
The warning light you may see
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General guidance for most cars, not a diagnosis of yours. Details differ by make, model and year - check your handbook, and if in doubt, don't drive.