A customer in the garden with an RAC Mobile Mechanic in the background.A close-up of a customer tending to her garden with an RAC Mobile Mechanic in the background.
Service, Repairs & MOT

Car diagnostic in Coulsdon

Book an RAC Mobile Mechanic and we’ll come to you at home or work

  • State of the art equipment
  • No hidden costs
  • Mechanics you can trust

Trustpilot rating for all RAC Mobile Mechanics.

Why choose the RAC for a car diagnostic?

With RAC Mobile Mechanics, you can avoid the hassle of taking your vehicle to a garage. They can do a vehicle diagnostic check on your driveway, so you don't even need to leave the house.

When it comes to diagnosing issues with your vehicle, our friendly expert mechanics are here to help. We use state-of-the-art diagnostic equipment to accurately identify any problems, ensuring your vehicle runs smoothly and safely. The price includes the diagnostic service – no hidden costs. Just friendly, honest experts.

Close up of an RAC Mobile Mechanic underneath a car

Our top pick in Coulsdon

We’ll come to you at home or work

RAC Mobile Mechanic in Coulsdon

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At the RAC, we’ve got over 125 years’ experience in offering complete peace of mind® to our members. We’re best known for our breakdown service. And now – our new RAC Mobile Mechanics are here to help make every day motoring easier. If you need a service or repair, they’ll come to you at your home or work.

Close up of an RAC Mobile Mechanic running a vehicle diagnostic check

Book a car diagnostic

Our mobile mechanics will spend up to 30 minutes checking your car for faults and talk you through any repairs you might need and give you a report for your records. There are various ways we can check for faults, which could include plugging in to check your car’s onboard engine management system.

We use original equipment manufacturer (OEM) standard parts, which means every new part will be the same standard and same quality as the original part it replaced.
Our mobile mechanics are friendly, honest, and backed by the RAC.
Close up of an RAC Mobile Mechanic running a vehicle diagnostic check

Book a repair

It’s easy to book a car repair online. We bring the garage to you with RAC Mobile Mechanics, or find a trusted local garage. Common repair jobs include:

We diagnose and repair clutch issues – whether your clutch is heavy or slipping, or you’re having trouble changing gears.
We check and correct alternator faults to keep your charging system running smoothly.
Oil is vital to a healthy engine, so it’s important to change it regularly.
If your brakes are making noise or you’re noticing reduced stopping power, it’s likely time to replace your brake pads or discs.

Average cost of a vehicle diagnostic by car make^

The RAC charges a flat rate for the cost of a car diagnostic but prices may change due to inflation. According to RAC data, the average cost of a car diagnostic is £87.

Make

Average price

Ford

£105

Vauxhall

£105

Volkswagen

£105

Peugeot

£104

Mercedes-Benz

£104

Nissan

£106

BMW

£107

Audi

£106

Renault

£104

Citroen

£104

^Average price quoted for RAC Mobile Mechanics from 01/01/25 to 31/03/25.

And it’s not just car diagnostics that we do in Coulsdon

Mobile mechanics bring the garage to you, saving you the hassle of getting your car to a garage. If you need a service or repair, they’ll come to you at your home or work.

A close up of an RAC mobile mechanic looking under the hood of a car

Try one of our RAC Approved Garages

KMK Automotive - Walton On The Hill

5.0/5

KMK Automotive is an independent family-run business based in Surrey, backed by more than 30 years’ experience in the industry. With auto repair garages in Leatherhead and Tadworth, we deliver exceptional vehicle repairs and services for all makes and models and our qualified mechanics complete jobs of all sizes to the highest possible standard. Whether you need to repair a fault, or your MOT test is due, our AA & RAC-approved auto centre has got you covered. For a high-quality, cost-effective alternative to main dealer services, get in touch with our fully insured team today.
Rear Of 14 - 16, Walton On The Hill, Tadworth, KT207RT

McCarthy Cars (UK) Ltd

McCarthy Cars (UK) Ltd As an RAC Approved business, you can trust us to deliver the best possible service, repair and MOT-testing results. McCarthy Cars is a multi-award-winning operation too. Our standalone Service Centre is based at 22 Silver Wing Industrial Estate, Horatius Way, Croydon, Kent (CR0 4RU), and is open every weekday, from 8am to 6pm. Horatius Way is accessible via Hannibal Way, which connects to Stafford Road (the B271), which itself links to the A23 and A232. The London Borough of Croydon features a number of railway stations too, with Waddon being the closest to our Service Centre. At Eurorepar Car Service, we’re all about keeping you and your car moving with confidence. As a trusted network of local garages, we provide high-quality car maintenance and repairs tailored to your needs – all at competitive prices. With our exclusive Brakes for Life program and a 2-year parts and labour warranty, you can drive away knowing you’re covered for the long haul.* Ask your Eurorepar Car Service Centre to fit Eurorepar branded parts to qualify. Claims under the 2-year parts and labour warranty must be made at a Eurorepar Car Service Centre. Discover expert care, unbeatable value, and peace of mind – all under one roof. Ready to experience the Eurorepar difference? Request a quote or give us a call today! *Terms and conditions apply.
Unit 22, Silverwing Industrial Estate, Croydon, CR04RU

Surrey Motor Services

Surrey Mot Centre is located in Norbury independent car garage specializing in mot & all types of repair work. We have fully qualified repair professionals If you are looking for a reliable Car repair & Service or MOT Testing Surrey Mot Centre is your local garage, at state-of-the-art premises based in Norbury. We provide a wide range of services and delivered quality results which make return customers as a majority of our customers come back. We offer free and accurate estimates on all repairs and only commence work once we have the consent of our customers. Although our expertise in MOT & regular repair and servicing, we also offer a range of services including all major and minor mechanical and electrical repairs, computer diagnostics, and bodywork. We have fully qualified trained staff who look after your car or van.
Unit 15 Tait Road, Cr0 2Dt, Croydon, CR02DT

B&W Motor Company.

Welcome to B&W Motor Company From our convenient location in South Croydon, we aim to offer our customers peace of mind that we can cater for all aspects of maintaining their vehicles in a cost effective and friendly manner. We deal with all makes of cars and LCV’s whether they are Privately owned, Company or Lease managed vehicles. We are delighted to have been invited to join the national network of RAC Approved Garages. The RAC have been serving motorists since 1897, and as the motorist’s champion, it’s their duty to provide motorists with a network of independent garages they can trust, that’s why they set up the RAC Approved Garages Network. As an RAC Approved Garage we follow the RAC Customer Charter for Approved Garages. This means you will get: Honest pricing – All work will be explained clearly and the costs will be transparent Quality work – Any repairs done will meet the high standard set by the RAC Exceptional customer service – You’ll find the service friendly, straightforward and jargon free For more information about the RAC and the Approved Garages network, please visit: www.rac.co.uk/approvedgarages Our range of services offer a winning combination of affordability along with the highest technical and customer service standards; whether basic servicing, diagnostics, wheel alignment, brakes, clutches or air conditioning.
57 Brighton Rd, South Croydon, CR26ED

Sutton Motors and Garage Limited

Sutton Motors and Garage Ltd is a reputable car repair and maintenance garage serving the Sutton area of South London. As a trusted local business, the garage provides a wide range of automotive services designed to keep vehicles safe, reliable, and roadworthy. These services include routine servicing, diagnostics, MOT testing, brake and clutch repairs, exhaust and suspension work, and general mechanical repairs. Mechanics at the garage are experienced and customer-focused, offering competitive pricing and professional expertise to address both everyday maintenance and more complex vehicle issues. Sutton’s busy roads and diverse driving conditions make reliable automotive care essential, and this garage plays an important role in meeting those needs for drivers in the Sutton community and surrounding areas.
292-300 Carshalton Rd Carshalton, Sutton, London, SM53QB

Frequently asked questions on car diagnostics

The cost you pay can vary depending on the type of car and how complicated the diagnostic test. Check with your mechanic for a quote.

Yes, a diagnostic test may save you a lot of money. It finds issues early before they become costly repairs. It can also keep your vehicle running efficiently and safely.

While you can buy a diagnostic tool, interpreting the results needs expertise. It’s best if you to have a professional mechanic perform the test.

Diagnostic tests take from 30 minutes to a few hours. This depends on what issues are being looked at.

Common diagnostic trouble codes include:

  • P0300: Random/Multiple Cylinder Misfire Detected
  • P0420: Catalyst System Efficiency Below Threshold
  • P0171: System Too Lean (Bank 1)

These are general examples, so your car may have different codes. Always check with a mechanic so you get an accurate diagnosis.

Yes, they are. Regular diagnostics can help keep your car in good health. It makes sure that underlying issues are addressed quickly, so you can drive with peace of mind on the road.

Again, keep in mind that mechanics might have their own checklists. Chat with your mechanic to be sure that they address any specific issues you have.