Car Diagnostics | Book a Car Diagnostic for your Mercedes

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.

RAC Mobile Mechanics can carry out car diagnostics on popular Mercedes models such as A-Class, C-Class, GLC, E-Class, and EQA. This service is completed at your home or workplace, following Mercedes maintenance guidance and using OEM‑equivalent parts. You get clear pricing, real‑time updates and a convenient, no‑hassle experience.

Close up of an RAC Mobile Mechanic underneath a car

Our top pick for your Mercedes

We’ll come to you at home or work

RAC Mobile Mechanic for your Mercedes

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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.

OEM quality parts

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.

Mechanics you can trust

Our mobile mechanics are friendly, honest, and backed by the RAC.

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:

Clutch Replacement

We diagnose and repair clutch issues – whether your clutch is heavy or slipping, or you’re having trouble changing gears.

Alternator repair

We check and correct alternator faults to keep your charging system running smoothly.

Oil change

Oil is vital to a healthy engine, so it’s important to change it regularly.

Brake pads & Discs

If your brakes are making noise or you’re noticing reduced stopping power, it’s likely time to replace your brake pads or discs.

And it’s not just car diagnostics that we do for your Mercedes

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

View all garages

Birway Total Vehicle Solutions

5.0/5

Established in 1972 we have grown into a total vehicle solutions centre combining traditional garage services to the local general public with transport logistics and vehicle fleet solutions to businesses on a nationwide scale. Part of the Hammonds Group, we are a multi-million pound turnover business working for Blue Chip organisations, Fleet Operators, Vehicle Finance Companies, Housing Associations & Banks. We provide them with a range of services including the movement of vehicles, servicing, accident repair and preparation for sale. Through impressive service, excellent teamwork, combined with our direct, ‘hands on’ approach we always look to deliver outstanding results to all of our customers. We are a professional company which prides itself on integrity, reliability and the speed in which we complete our services. Working in partnership with our clients, we provide a tailor-made and cost effective solutions for all your vehicle needs. As an approved Ministry of Transport Testing Centre and membership of BVRLA, Retail Motor Industry Federation, Good Garage Scheme and the Motor Industry Code of Practice, and in conjunction with ISO 9001 & ISO 14001 accreditations you can be assured that we operate to rigorous standards.

90 Newhall Street, Willenhall, WV13 1LQ

Brooklands Service Centre

4.7/5

Brookland's have been here for 30 years. We are proud in everything we do and carry everything out to a high spec. Brookland's technicians carry over 15 years of experience an have delt with many aspects of different makes and models over the year, they all carry the correct qualifications from MOT license's to NVQ 2&3. We ain’t afraid to to take on any job an work constantly around the clock the get vehicles back on the road the same day. We carry out a wide range of diagnostic test's and checks, to service and repairs we also do mot's. As on the other hand we also carry out a wide range of body work and repairs too..

162 Armley Road, Leeds, LS122TY

Duke Street Motors

4.2/5

We are an established local independent garage and are proud to be members of Autofirst Network – a nationwide network of independent garages operating to the Network’s 6 core values of Capability, Consistency, Care, Clarity, Cost Effectiveness and Customer Focus. For your added peace of mind we are members of the Motor Ombudsman service which is approved by The Trading Standards Institute. In short, we are a local garage you can trust offering you the support and service guarantees of a national network, giving you complete peace of mind.

6 King Edward Road, Loughborough, LE111RZ

IN'n'OUT Autocentres Bracknell

4.2/5

At IN’n’OUT Autocentres we offer fixed prices MOTs and Servicing for any make and model of car with no hidden extras. We are proud to be a ‘Which? Trusted Trader’ so we are really a garage you can trust. We also have a 5 Star Trustpilot reviews rating. We provide OEM parts and 12 months warranty on all parts and servicing. We only use premium Castrol oils in all servicing. Our services are all completed ‘while-u-wait’ so you have never have the inconvenience of losing your car for the day. You can watch your car as it is being worked on through the viewing window or sit back and relax in our clean and comfortable customer lounges with FREE Wi-Fi and coffee and read the latest magazines. Check out our latest reviews and BOOK NOW!!

Unit 5B Western Trade Centre, Western Rd, Bracknell, RG121RW

QCD Autocentre Brackley

4.8/5

QCD Autocentre Brackley has been established to offer customers quality workmanship, cost-effective solutions and delivery on-time. Our mission is to deliver a new level of transparent service and experience for customers in Brackley not usually familiar to the vehicle repair and maintenance industry. All our workshops are fully equipped with the latest tools and hi-tech equipment, so vehicles are maintained to exacting manufacturer standards. We believe in providing customers with cost-effective automotive solutions and complete service transparency. We invest in the latest technologies to bring you a high-level of service. Our offering includes convenient hassle-free online bookings for MOTs, vehicle servicing and easy to use ordering system for tyres.

Units 5-7 Highpoint, Riding Road, Buckingham Industrial Estate, Brackley, NN137BH

Frequently asked questions on car diagnostics

How much does it cost to diagnose a car problem?

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.

Is a car diagnostic test worth it?

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

Can I do a car diagnostic myself?

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.

How long does a car diagnostic test take?

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

What are common car diagnostic codes?

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.

Is a car diagnostic test necessary for a service?

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.