Car Diagnostics | Book a Car Diagnostic for your Mercedes

Trustpilot rating for all RAC Mobile Mechanics.

Why choose the RAC for a car diagnostic?

At the RAC, we've got over 125 years' experience helping UK drivers. We have the skills and knowledge to keep your vehicle running.

Plus, with RAC Mobile Mechanics, you can avoid the hassle of taking your vehicle to a garage when you need a repair. We’ll come to you, at your home or work.

Close up of an RAC Mobile Mechanic underneath a car

Our top pick for your Mercedes

Our top pick

RAC Mobile Mechanic for your Mercedes

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.

A customer tending to her garage with an RAC Mobile Mechanic in the background

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.

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:

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

Cavanfields Autocentre.

4.6/5

We have been established for over 18 years now, and are very proud of the excellent reputation that we have built up. We are proud to offer you a first class customer service and very competitive pricing, so please browse our stock list. At Cavanfields Uk Ltd we stock a range of used cars to suit all budgets and lifestyles so we are sure to have the right car for you.

Pennings Road, Tidworth, Salisbury, SP97SU

Farnsfield Auto Centre

4.3/5

Farnsfield Auto Centre is a family owned garage servicing all your vehicle needs in Nottingham, Farnsfield and Newark areas. We are a full serviced garage located in Southwell Road in Farnsfield. Servicing cars and vans in the local area has provided us with a 2nd to none customer service and reputation. Our reputation is built on quality and efficiency when it comes to automotive servicing sector. Our technicians are all fully qualified and highly trained, and are always available to answer your questions around car problems or parts in the Nottingham, Farnsfield and Newark areas.

Southwell Road, Farnsfield, Newark, NG228EB

Darlington Mot Centre

4.9/5

Darlington Mot Centre Mot cars, vans , motor homes , motorbikes , trikes ,quads • Comfortable reception to wait in • Motorcycle class 1 and 2 only £25 • Class 4 cars and vans only £45 • Class 7 & motor homes up to 3.5ton only £50 • MOT's carried out up to 28 days before expiry - keep your original expiry date • Post card reminder service so you never forget your MOT again • Free re-test within 10 working days • No charge for head light adjustments We service and repair all makes of vehicles All makes serviced and repaired • Full and Interim service • Body shop repairs for those little scrapes, dings and re-sprays • Air-con new and old gasses repairs • Timing belts and engine repairs • Brake disks and pads • Exhaust and suspension • Tracking 4 wheel alignment • Tyres new and part worn • Batteries, starters and alternators • Diagnostics and engine management systems • Clutches and gear boxes

Darlington Mot Centre, 410 Whessoe Road, Darlington, DL3 0RP

IN'n'OUT Autocentres Bristol

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!!

In-N-Out Autocentres, Cribbs Causeway, Bristol, BS10 7UD

A1 Tyres and Exhausts

5.0/5

With over 30 years experience of automotive repairs in Coventry, A1 Tyres and Exhausts is a name that you can rely on to deliver a professional, high quality, and reliable service, that will meet all of your car needs. And above all, we are a name you can trust again and again.

Unit 12-13, Relton Mews, Coventry, CV65HE

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.