Car diagnostics test

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Average quote for diagnostics testing

What is a diagnostic test on a car?

Sometimes, when you experience car trouble, it’s easy to know that something is wrong but more complicated to determine precisely what is causing the problem.

A diagnostic test involves a professional connecting your car to a scanner and revealing the issue by interpreting the error codes related to a specific fault. Whether it’s your exhaust, engine, transmission or brakes, a diagnostic test can help you pinpoint the problem and then get the proper repair.

Car diagnostic average costs and prices

A car diagnostic is a relatively cost-friendly service. Running the diagnostic test costs £51.66 on average, but that doesn’t include any repairs or work you might need afterwards.

Car MakeAverage Price

Which car diagnostics service do I need?

There’s only really one type of car diagnostic test, although the technology used to carry out the test might differ between garages. The test will be able to reveal issues with your car’s engine, transmission, brakes and more – it’s the fix itself that will vary based on what the diagnostic test picks up.

  • Diagnostic test

    The average cost of a car diagnostic test booked on WhoCanFixMyCar is £51.66.

    A car diagnostic test is a digital analysis of your car, undertaken by a specialist mechanic, to assess potential faults and issues with your car engine, transmission, brakes and many more.

    Can include
    • Diagnostic test
  • Mobile car diagnostics

    The average cost of mobile car diagnostics booked on WhoCanFixMyCar is £52.33.

    Mobile diagnostics testing involves a specialist coming to you and running tests on your vehicle to expose the cause of any problems you're having with your car.

    Can include
    • Home visit
    • Full diagnostic testing
    • Recommended repairs
  • Car electrical diagnostic

    The average cost of a car electrical diagnostic booked on WhoCanFixMyCar is £62.34.

    The more complicated part of fixing a problem with your car’s electrical system is figuring out exactly what’s going wrong in the system and where the fault is located. A car electrician will carry out a diagnostics test to pinpoint the exact source of the issue and recommend the appropriate repair.

    Can include
    • Car electrics inspection
    • Car electrical fault diagnostic test

What do car diagnostics tell you?

The useful thing about a car diagnostic is that you don’t need to know what it is you’re looking for before you get the test. The clever technology will connect to your car’s computer system and reveal faults with any component connected to the vehicle’s engine control unit (ECU).

A car diagnostic test is a full inspection of your car’s ECU that can be used to reveal any issues with: 

  • Engine

  • Exhaust

  • Transmission

  • Ignition

  • Fuel injectors

  • Coils 

  • RPM levels 

  • Air and coolant temperatures

  • Battery

  • Bulbs

  • Oil tank 

  • Throttle

  • Steering

  • Gears

  • Crankshaft

  • Camshaft

These are just some of the issues your diagnostic can detect. Furthermore, your diagnostic test will be able to reveal any issues with many more components that you might not even know existed.

When do I need a car diagnostic?

A car diagnostic will normally be recommended by a mechanic if you have symptoms of car trouble that are affecting your ability to drive correctly and the mechanic can’t visually see what the problem is. Diagnostic tests are particularly beneficial if there’s an issue with your engine, as it’s not usually clear which of its many components has the fault.

Car diagnostic tests aren’t a part of regular car maintenance, so if you’re not experiencing any issues with your car, you won’t need a diagnostic test. Instead, just make sure to keep on top of your car’s routine maintenance by getting an annual MOT and service. Similarly, if a mechanic can immediately see what the problem is with your car when you bring it to a garage, you won’t need a diagnostic either.

That said, diagnostic tests can be a useful tool if you’re buying a used car. A used car diagnostic test works in exactly the same way as a diagnostic test that takes place when you’ve experienced an issue with your car. The difference is that the car may not be displaying any signs of damage – instead, the test is designed to flag up any issues that might not be obvious before you commit to buying it. If you want to have a diagnostic test on a used car you’re considering purchasing, you’ll need to get the seller (whether it’s a private seller or a professional car dealer) to agree to it. If they don’t, that should act as a red flag and it’s probably prudent to walk away.

Car diagnostics testing

Cover image

If you wanted to try to diagnose any issues with your car, why not take a look at this guide that will help you diagnose what's wrong with your car. We'll help you make sense of every strange smell, sound and feeling coming from your car so you can go to your local mechanic with a good idea of what the issues potentially are.

What impacts the car diagnostic price?

There’s a reasonably large range of prices you could pay for a diagnostic test on your vehicle and many different factors that impact the result. The most significant variables include: 

  • The make of the vehicle

  • The model of the vehicle

  • The size of the engine

As a general rule, the larger your car and the more valuable the make and model, the more you will end up paying for a diagnostic test and any additional repairs.

Paying for a car diagnostic vs free car diagnostic checks

Car diagnostic tests can vary in price but are sometimes advertised as ‘free’. However, this is usually caveated. You’ll often need to pay for the cost of a repair off the back of the diagnostic test, and so the price of the scan itself is usually baked into that. It’s unlikely you’ll be able to find a diagnostic test that is truly free of any charge.

A vehicle health check, however, is sometimes free. A garage may perform this simple visual inspection of your car as a way to build a relationship with you and get you to come to them again in future.

Where can I get car diagnostics near me?

You can get a car diagnostic test at any licensed garage. Most auto repair shops will have a technician on-site who can effectively perform and read the results of a diagnostic test.

Find mobile diagnostics specialists near you

Because many of us have busy schedules, it's often more convenient for a mobile specialist to visit your home and carry out a service or repair there for you, meaning you don't have to find the time to get your car to the garage.

Many garages and mechanics in our network here at WhoCanFixMyCar are able to offer a mobile diagnostics service, so you can enjoy the convenience of a mobile specialist carrying out your diagnostic test from your home. Simply enter your registration and postcode to compare prices from mobile diagnostic garages near you.

How much does a full diagnostic cost?

A car diagnostic test costs on average £51.66, although the exact price will depend on the type of vehicle you have. It’s unlikely that your car diagnostic would cost more than £100.

How long does a car diagnostic take?

A car diagnostic test is a relatively quick service, taking around 30 minutes. However, any subsequent repairs you need will usually take much longer.

How much is the average engine diagnostic price?

An engine diagnostic is usually just another term for a car diagnostic test, which will reveal issues with a range of car parts including the car engine. The average engine diagnostic price varies widely, but you can expect to pay around £50.

Does a car diagnostic test fall under warranty?

A car diagnostic test doesn’t usually fall under warranty, but any repairs you need as a result may. It’s important to check your policy documents to find out if the service you need is covered.

Is car diagnostics covered by insurance?

Your car insurance doesn’t typically cover a car diagnostic test, but you may be able to claim for any repairs you need after the test. It’s important to check your documents to determine if your insurance policy covers the service you need.

Do I need to book a car diagnostic test for a leased car?

Not always, but if there’s an issue with your leased car that requires a car diagnostic test to identify it, then yes. You're responsible for repairing and maintaining your leased car. So, although you don’t technically have to get your car a diagnostic test, if a professional believes that one is needed to get to the root of a problem with the vehicle, it might be necessary to maintain your lease agreement.

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