Book a Car Diagnostic in Watford

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 Watford

We’ll come to you at home or work

RAC Mobile Mechanic in Watford

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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.

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 Watford

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

Brookdene Service Centre

Brookdene Motors has been established for over 25 years, offering general repairs and servicing to Watford and the surrounding areas. We are specialist in VW, Audi, Seat, and Skoda. Reputation and trust are key business tools for any independent garage and at Brookdene motors in New Road, Watford, its part of the firm's philosophy. Reputation is a very important word for the team - which explains why Brookdene Motors is celebrating over 25 years in the industry. We are also now proudly part of Elite Remaps. If you need further endorsement, many of our huge database of loyal customers have been using the garage since its very early days when it was situated in Carpenders Park. Now our location is ideal, situated at the edge of Waterfields Retail Park just behind Tesco and only three minutes walk to The Harlequin and Lower High Street Station. Brookdene Motors offers a full range of services and our busy and highly competent staff are all long-serving, With the senior technician being with the garage for over 24 years. We have invested heavily in the latest diagnostics equipment and the facilities also include an automatic tyre charger and a computerized wheel balancer. All our parts come with a standard manufacturer warranty and our labour is guaranteed for 1 year.

10-12 New Road, Lower High Street, Watford, WD17 2EX

Nexa Max Garages

Professional car repair and MOT service in Watford (WD24 7GP), focused on quality, reliability, and expertise. We provide high-quality repairs, diagnostics, and servicing for all brands. Our experienced team precisely handles engine repairs, brakes, suspension, transmissions, retrofits, and multimedia installations. Equipped with the latest tools, we ensure fast, efficient, and expert service. Book your appointment today!

Unit A, 2 Greycaine Road, Watford, WD247GP

Johnson Motors

We are the approved dealer for the community-áKeep Spending Local Scheme for Watford. We have been providing a first class service for the Watford and surrounding areas for a many years offering service and repair to all makes of cars and light vans, to corporate, fleet and the private sector. Over the years we have built an excellent reputation for our quality workmanship and friendly service. All our fitters and technicians are fully trained and are constantly updated with changes or enhancements made by car manufacturers of all makes. Our team pride themselves in the ability of diagnostics and fault finding, saving you expensive exploratory time that may be incurred at some other garages." We are the only RAC Approved garage in Watford (we service the RAC patrol vans ) we are also AA approved Warranty repairer so the standard of our work is very high.

Unit 5 Moor Park Industrial Centre, Tolpits Lane, Watford, WD18 9SP

The MOT Centre

Based in Hatch End, The MOT Centre has a team of expert mechanics on hand to deal with all your car repair requirments. Our repair service uses the most up to date tools and equipment to repair any make and model of car. We keep most a range of parts in stock, or parts can be delivered within the hour by one of our suppliers, so most work can be done while you wait. We can undertake insurance work and also offer sub-contracted work.

Cornwall Road, Hatch End, Piner, HA54LS

Goodmans Autos

Established in 1962 we have been at our current premises in Borehamwood for the last 11 years. If you're looking for top quality car servicing from people you can trust, you've come to the right place. And if you're looking to save money on what it costs to service and maintain your car you've come to the right place too. That's because you get the best of both worlds ÔÇô quality and price ÔÇô when you choose Goodmans Autos. You get complete peace of mind with our fully qualified staff and genuine quality parts. And we won't do any service work or any repair without getting your agreement first.

16-20 Shenley Road, Borehamwood, WD6 1DS

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.