Is it safe to drive with this code?

Driving may be possible for short distances, but unpredictable stalling—especially at junctions or roundabouts—can present a safety risk. It's advisable to have the vehicle inspected promptly; see our site disclaimer for further guidance.

An illuminated Check Engine Light at the time of the MOT test may result in a failure under emissions and system monitoring checks. The fault itself does not guarantee failure, but the MIL presence typically does—refer to our disclaimer for MOT-related detail.

Roughly how much does it cost to fix?

If the issue is resolved by cleaning the throttle body and repairing wiring, costs often remain in the low two-figure range for parts and supplies. Replacing an idle air control valve typically falls into the low three-figure bracket at an independent garage, while main dealers or more complex diagnoses (vacuum leaks, ECM faults) can push costs toward the mid three-figure range, depending on labour rates and vehicle make.

Can a dirty throttle body really cause this code?

Yes—carbon build-up in the throttle body bore is one of the most commonly reported triggers for P0518, as it can prevent the idle air control valve from maintaining stable airflow. Many technicians recommend cleaning this component before replacing other parts.

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← All fault codes | Electrical & Sensors

P0518

Powertrain

Idle Air Control Circuit Intermittent

The engine control module has detected an inconsistent signal from the idle air control system, which typically regulates engine speed when the throttle is closed.

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ⓘ Information only. This page provides general educational information about fault code P0518. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P0518 mean?

P0518 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Idle Air Control Circuit Intermittent.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

About Electrical & Sensors codes

Codes in the Electrical & Sensors category.

P0518 is one of 4,010 codes in this category. Browse all Electrical & Sensors codes →

What we know about P0518 specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P0518.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

•your vehicle's own service manual or manufacturer-specific technical bulletins
•a qualified mechanic with a manufacturer-level diagnostic tool
•a marque specialist familiar with your make and model

Codes nearby

Codes adjacent to P0518 in the P-code series. Many fault codes appear together with their neighbours because they relate to the same circuit or component.

P0515 Battery Temperature Sensor Circuit

P0516 Battery Temperature Sensor Circuit Low

P0517 Battery Temperature Sensor Circuit High

P051A Crankcase Pressure Sensor Circuit

P051B Crankcase Pressure Sensor Circuit Range/Performance

P051C Crankcase Pressure Sensor Circuit Low

Other Electrical & Sensors codes

Other fault codes in the same system as P0518. The ones with detailed guides have plain-English explanations, symptoms, causes, and diagnostic steps.

B1257

Air Temperature External Sensor Circuit Short To Ground Detailed guide

B1363

DBPT Circuit Short To Ground Detailed guide

B2100

Ignition Run/Start Input Circuit Performance Detailed guide

C2000

Steering Angle Sensor Not Calibrated Detailed guide

P0030

HO2S Heater Control Circuit (Bank 1 Sensor 1) Detailed guide

P0031

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1) Detailed guide

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P0518 can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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