Car Diagnostics | Book a Car Diagnostic in London

£50.02

Average price for this repair in London in the last 30 days^

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 in London

Our top pick

RAC Mobile Mechanic in London

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.

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 in London

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.

Try one of our RAC Approved Garages

View all garages

Millennium Garages Ltd - RAC Approved Garage

5.0/5

Millennium Garages is based in Southwark, London offering MOTs, Services and Car Repairs using industry-standard equipment and fully trained staff with over 40 years of experience in the motor industry. Since 2019, Millennium Garages Ltd has been a RAC Approved Garage. ALL Customers, Including RAC Warranties, are responsible for paying Congestion Charge and ULEZ when required for their vehicles.

Arches 43 - 47, Kings Bench Street, London, SE10QX

Andrews garage

4.7/5

Established since 1974 Andrews Garage has been serving the local area for all its car related needs, such as, MOT'S, Servicing, Tyres, Bodywork (crash repairs), 3D 4 Wheel alignment, Air conditioning Re-gassing.

30-36 Padfield Road, London, SE59AA

Tyre World & MOT Station

4.6/5

TYRE WORLD WAS ESTABLISHED IN 1992 TO PROVIDE MOTOR VEHICLE SERVICE AND GREAT TYRE SERVICE IN LOCAL AREA. We do following services: 1. 4 Wheel 3D Alignment. 2. Tyre 3. MOT 4. Tyre Replacement 5. Mechanical Work

10-11 Williams Buildings, Bethnal Green, London, E20LF

West Hampstead Motors Ltd

4.5/5

Established in 1975. West Hampstead Motors Ltd. are expert in the servicing and repair of both classic and modern German vehicles. We specialise in Audi, BMW, Mercedes Benz, Porsche and VW cars. Alongside the service centre, our state of the art approved bodyshop undertakes all aspects of body work and restoration to the highest of standards.

155-161, Grafton Road, Gospel Oak, NW5 4AY

MNS Autos Ltd

4.2/5

At MNS Autos, we are dedicated to keeping our customers on the road. Our commitment lies in providing a fully comprehensive service that our customers deserve. We pride ourselves on delivering quality workmanship, using only approved parts, all at competitive prices. We welcome you to try us out and see yourself the difference. Thank you

196 Barnardo Street, London, E10LL

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.