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OBD fault code guide

P0507 Code Meaning UK

P0507 means “Idle Control System RPM Higher Than Expected”. In plain English, the engine is idling faster than the ECU wants it to. Common causes include a vacuum leak, dirty throttle body, idle air control fault, PCV leak, split intake hose, throttle body adaptation issue, stuck throttle plate or air leak after the MAF sensor.

📅 Updated June 2026 🇬🇧 UK diagnostic guide 🛠 High idle fault
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✓ P0507 meaning ✓ High idle checks ✓ UK repair costs ✓ MOT-aware advice
Quick answer Meaning Symptoms Causes Diagnosis Idle checklist Repair costs Can you drive? MOT impact Related guides FAQs
Quick answer

What does P0507 mean?

P0507 means the idle speed is higher than the ECU target. The ECU tries to control idle using the throttle body, idle air control system, fuelling and sensor feedback. If extra air enters the engine or the throttle control is not behaving correctly, the idle speed can rise above target and trigger P0507.

Most likely area

Vacuum leak, throttle body, idle air control valve, PCV system, intake hose, MAF reading or idle relearn.

Urgency

Moderate if idle is slightly high, higher if the car surges, creeps or feels unsafe in traffic.

MOT risk

Can affect warning light status, idle stability, emissions and test behaviour.

Code meaning

P0507 — Idle Control System RPM Higher Than Expected

The full description is usually P0507 Idle Control System RPM Higher Than Expected. This means the ECU sees the idle speed sitting above the desired target. For example, the ECU may want the engine to idle around normal idle speed, but the engine is revving higher even when the accelerator is not pressed.

On older vehicles, the issue may involve an idle air control valve. On newer vehicles, it often involves an electronic throttle body, throttle adaptation, vacuum leak, PCV leak or intake air leak.

Mechanic view

Why P0507 is usually an air-control problem

A high idle usually means the engine is getting more air than expected, or the throttle control system is not matching the ECU target. That extra air can come from a split hose, leaking PCV valve, intake gasket leak, dirty throttle plate or throttle adaptation problem.

The best diagnosis is to check actual idle speed, throttle angle, air leaks and fuel trims before replacing parts.

Symptoms

Common symptoms of a P0507 code

P0507 is normally noticeable at idle, when stopping, parking, sitting in traffic or selecting gear on an automatic.

High idle speed

The engine may idle higher than normal when warm.

Revs hanging

The revs may stay high for too long after lifting off the accelerator.

Car creeps strongly

Automatic cars may pull forward more than usual when in Drive.

Surging idle

Idle speed may rise and fall as the ECU tries to regain control.

Engine warning light

A steady engine management light may appear with P0507 stored.

Poor fuel economy

High idle and air leaks can increase fuel use, especially in town driving.

Common causes

What causes a P0507 fault code?

P0507 is commonly caused by extra unmetered air entering the engine or the throttle/idle control system not adapting correctly.

Very common

Vacuum leak

A split vacuum hose or intake leak can allow extra air into the engine.

Throttle body

Dirty throttle body

Carbon around the throttle plate can affect airflow and idle control.

Adaptation

Throttle body relearn needed

After cleaning, battery disconnection or repair work, some cars need idle/throttle relearn.

PCV system

PCV valve leak

A leaking PCV valve or breather system can create an internal vacuum leak.

Intake hose

Split intake hose

Air entering after the MAF sensor can make idle speed and fuel trims unstable.

Idle valve

Idle air control valve fault

Older vehicles may use an idle air valve that can stick or fail.

Throttle

Sticking throttle plate

A throttle plate that does not close properly can cause a high idle.

Sensor data

MAF or MAP sensor issue

Incorrect airflow or pressure data can make idle control inaccurate.

Gasket leak

Intake manifold gasket leak

A gasket leak can let unmetered air enter and raise idle speed.

Diagnosis

How a garage should diagnose P0507

✅ Scan all stored, pending and permanent codes.

✅ Record freeze frame data before clearing anything.

✅ Check actual idle speed against target idle speed.

✅ Inspect intake hoses, vacuum pipes and PCV hoses for splits.

✅ Smoke test the intake system for air leaks.

✅ Check throttle body cleanliness and throttle plate movement.

✅ Check fuel trims for signs of unmetered air.

✅ Check MAF and MAP sensor readings.

✅ Perform throttle body or idle relearn where required after repairs.

Avoid this mistake

Do not clean the throttle body and skip relearn

Throttle body cleaning can help, but on some vehicles the ECU needs a relearn procedure afterwards. If the relearn is skipped, the idle can stay high or unstable.

Also, if the real fault is a vacuum leak or PCV leak, cleaning the throttle body will not fix P0507.

High idle checklist

Mechanic-style checks for P0507

A strong P0507 diagnosis should prove whether the high idle is caused by extra air, throttle control, sensor data or ECU adaptation.

Target vs actual idle

Compare desired idle speed with actual RPM on live data.

Smoke test intake

Find hidden vacuum leaks around hoses, gaskets and PCV pipework.

Fuel trim check

Positive fuel trims can support an air leak diagnosis.

Throttle angle

Check whether the throttle is closing to the expected position.

PCV test

Check for a split breather hose, stuck PCV valve or crankcase air leak.

Idle relearn

Perform the correct relearn/adaptation after cleaning or repairs where required.

UK repair cost guide

How much does P0507 cost to fix in the UK?

Costs vary depending on whether the fault is a simple vacuum leak, throttle cleaning, PCV repair, idle relearn or throttle body replacement. These are rough UK guide prices only.

Diagnostic scan and idle check

Usually around £40–£120 depending on live data and smoke testing depth.

Vacuum hose repair

Often modest if the split hose is easy to find and access.

Throttle body cleaning

Moderate cost depending on access and whether relearn is required.

Idle/throttle relearn

May be included with diagnosis or charged separately depending on the garage.

PCV valve or breather repair

Cost depends on engine layout and whether the PCV is built into another component.

Throttle body replacement

Can cost more if the electronic throttle body is faulty and needs replacement.

Safe driving advice

Can you drive with a P0507 code?

Short careful driving may be possible if the idle is only slightly high and the car remains controllable. But if the revs are very high, the car creeps strongly in gear, surges, stalls, or feels unsafe at junctions, get it checked quickly.

✅ Lower risk: steady engine light, slight high idle, no surging and normal control.

⚠️ Medium risk: revs hanging, rough idle, poor economy or repeated warning light.

🚫 Higher risk: very high idle, strong creep in automatic, surging, stalling or unsafe control.

Real experience

What I would check first

On a real P0507 job, I would listen for air leaks and check fuel trims before touching parts. If the trims show the ECU adding fuel at idle, an air leak becomes a strong suspect.

Then I would inspect the PCV system and throttle body. A split breather pipe or dirty throttle plate can easily cause a high idle, especially after previous repair work.

MOT implications

Will P0507 fail an MOT?

P0507 can lead to an MOT failure if it causes an emissions-related engine warning light, unstable idle, excessive emissions, rough running or unsafe engine speed behaviour. A very high or surging idle should be repaired before testing.

Engine warning light

An emissions-related engine light should be investigated before MOT.

Idle stability

A surging or very high idle can affect emissions and test behaviour.

Air leak issue

Vacuum leaks can affect fuelling, emissions and running quality.

Engine light MOT guide Emissions MOT guide
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Browse more OBD fault code guides

P0507 is one common idle control and high idle diagnostic trouble code. For more common codes, meanings, symptoms, repair costs and MOT implications, use the main Motor Vehicle Expert fault-code hub.

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Frequently asked questions

Frequently Asked Questions About P0507

Find answers to common questions about P0507 high idle faults, vacuum leaks, throttle body problems, repair costs and MOT implications.

What does P0507 mean?

P0507 means the engine computer has detected that the idle speed is higher than expected. The engine is revving above the target idle speed even though the ECU is trying to control it.

Can I drive with a P0507 code?

Short careful driving may be possible if the car is controllable and the idle is only slightly high. If the car surges, revs very high, creeps forward strongly in gear, stalls, or feels unsafe at junctions, get it checked quickly.

Will P0507 fail an MOT?

P0507 can lead to an MOT failure if it causes an emissions-related engine warning light, unstable idle, poor emissions, obvious running fault or unsafe engine speed behaviour during the test.

What causes a P0507 code?

Common causes include a vacuum leak, dirty throttle body, throttle body adaptation issue, faulty idle air control valve, PCV leak, intake hose split, stuck throttle plate, air leak after the MAF sensor or ECU idle relearn issue.

How much does P0507 cost to fix in the UK?

A diagnostic check may cost around £40 to £120. Throttle body cleaning, vacuum leak repair or idle relearn may be moderate, while throttle body, PCV or intake repairs can cost more depending on the vehicle.

Can a vacuum leak cause P0507?

Yes. A vacuum leak is one of the most common causes of P0507 because extra unmetered air can raise idle speed above the ECU target.

About this guide

Based on practical mechanic-style diagnostic experience

Motor Vehicle Expert publishes practical UK vehicle guidance based on real-world mechanical knowledge and hands-on diagnostic experience. This P0507 guide is written to help drivers understand high idle and idle control faults before replacing parts unnecessarily.

Fault codes should always be treated as a starting point for diagnosis. If your car has a very high idle, surges, creeps strongly in gear, stalls or feels unsafe to control, get professional help before continuing to drive normally.