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What is car remapping, and how will it affect my car insurance?

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Car remapping improves your vehicle’s performance by modifying its on-board computer’s programming to alter various engine settings.

Engine remapping can be a cost-effective way to get the most out of your car. This type of modification can make your vehicle easier to drive and improve your engine’s fuel efficiency.

But remapping can make it harder and more expensive for you to get car insurance quotes because insurers think of remapping as a vehicle modification. Some companies don’t insure remapped cars at all. Other providers charge higher premiums. It’s important to note that if you have your car remapped, its warranty is likely to become invalid.

This guide tells you everything you need to know about the benefits and costs of remapping your car and explains the impact that remapping can have on your car insurance.

How does car remapping work?

Car remapping involves altering the settings of a car’s electronic control unit (ECU), which is also referred to as an engine control unit. Here are three other names for remapping:

  • Engine remapping
  • ECU tuning
  • Chipping

Remapping should only be done by a professional who uses specialist software and diagnostic tools. You can take your car to a local garage to get it remapped, or you can have a mobile car remapping service come to your home or workplace to do the job.

Make sure you find a reputable business to remap your car. Some remapping specialists have been certified by the Institute of the Motor Industry

You should never let an amateur attempt to remap your car. Doing it wrong could damage your car, invalidate your car warranty and void your car insurance.

How does car remapping improve my car’s performance?

Your car’s ECU comes with its own preset configuration that limits its performance capabilities. The remapping process overwrites this configuration.

Remapping can improve your car’s throttle and engine response and result in increased fuel economy. You can have your car remapped to enable it to go faster and perform well at high altitudes. 

Modern technology makes it possible to overwrite the ECU chip inside your vehicle by plugging a laptop or handset into the car’s on-board diagnostics port, but not every car can be remapped in this manner.

For example, modifying ECU chips in vehicles made before the year 2000 involves manually removing them and retuning them or replacing them with new ones. Some current-day manufacturers lock the chips in their cars to prevent remapping.

The types of cars that are most commonly remapped have turbo diesel engines with TDI, HDi or CDTi designations. Remapping these cars generally achieves the biggest performance improvements for a relatively low cost, but most modern cars with petrol engines can also be remapped.

Advantages of remapping a car

The advantages of remapping your car can include:

  • Altered ignition timing and fuel flow, which result in better acceleration and adaptability
  • Improved throttle response
  • Engine customisation that’s suited to the altitude where you live
  • Extra power when climbing
  • Better fuel consumption
  • Improved turbocharger boost pressure
  • Added power for towing a trailer or caravan

Disadvantages of remapping a car

The disadvantages of remapping your car can include:

  • More wear and tear on the engine
  • Added stress on the engine, which could cause car components to fail sooner than they otherwise would
  • The necessity for more frequent servicing
  • A potential increase in fuel costs
  • The invalidation of your warranty if your car’s manufacturer or dealer doesn’t approve the remapping
  • Increased car insurance premiums or greater difficulty in obtaining insurance
  • The possibility that your existing car insurance policy will be cancelled if you don’t tell your insurer about the remapping
  • The possibility that the leasing company won’t allow you to remap your leased/personal contract hire car

Car remapping normally costs between £200 and £400.


Several factors impact the cost of remapping your car:


  • The car’s make and model
  • The engine type (namely, whether it is a petrol engine or a diesel engine)
  • The complexity of the ECU system, which can be more intricate in premium or high-performance cars 
  • The specific ways you want remapping to improve your car
  • The cost of labour


Remapping costs around £1,000 if it includes the use of new parts, such as air filters or an exhaust. If the job includes extensive changes to your car’s engine, you could wind up paying thousands of pounds.


Many professional remappers will give you personalised online quotes for remapping your car.

What will happen to my car insurance if I remap my car?

Insurance companies consider engine remapping to be a modification. They generally charge higher premiums for modified vehicles.

When you generate a car insurance quote, you’ll be asked if your car has been modified. If you have had your car remapped, you should answer “yes”.

The insurer or price comparison site will then ask for details about the modifications. Remapping typically falls under a category that is labelled “engine” or “engine and transmissions”. 

The options include various increases to brake horsepower, which takes the friction between your car’s tyres and the road into account when measuring the power your engine generates. Other options focus on transmission changes, turbocharging and issues such as whether the engine has been bored out or replaced.

To obtain accurate insurance quotes, you must be honest and precise about the extent of the remapping you have had done. When you improve your vehicle’s performance, you make it a higher-risk car and increase the insurer’s risk.

If you have car insurance before you get your car remapped, you must tell your insurer about the remapping after the job has been completed. If you fail to inform your insurer about remapping or other modifications, your policy could be invalidated. This could result in the rejection of any claims that are made.

Insurers usually increase the premiums for remapped cars. Some insurers refuse to provide coverage for them. If you need to look elsewhere for cover, be sure to get quotes from specialist insurers that provide modified car insurance.

Do I need to tell the DVLA about remapping?

If you’ve had your vehicle remapped, you need to notify the Driver and Vehicle Licensing Agency (DVLA) by updating the V5C log book the agency issued when your car was registered in the UK.

In general, you must update your V5C whenever you change your vehicle’s colour, engine, cylinder capacity, fuel type, seating capacity, vehicle identification number or wheel plan.

You must give the DVLA evidence, such as a receipt, an inspection report or a letter from the garage, that confirms you made changes to your car. The agency will inform you if you need to have your car inspected.

Car remapping FAQs

Remapping is usually safe if a qualified, experienced professional uses the right equipment to do it, but increasing your engine’s power may impact your car’s reliability because it adds stress to your engine.

It’s not a good idea for amateurs to try to remap their cars by following instructions they find online. DIY remaps can go wrong and damage car engines.

When you buy a car, you should ask the seller if it’s been remapped. If you don’t trust them to answer truthfully, you can pay a remapping company to examine the ECU with specialist technology.

When you sell your car, you should tell your buyer if you’ve remapped it. Your buyer needs to know about the modifications you’ve made to it so they can get the right car insurance. 

You should give the buyer documentation that provides information about the remap, including the remapping specialist’s name, the remap date and the ECU settings’ changes.

As was previously mentioned, you should include the remapping details in your car’s V5C log book. The new log book the DVLA sends the buyer will include that information.

If you drive a leased car, you’ll need the leasing company’s permission to make any type of modification, including remapping. Most companies allow you to remap their vehicles if you can reverse the changes when your lease ends.

If you don’t ask your leasing company whether you can remap your car, you could have your car warranty invalidated or be penalised when you return the vehicle by having to cover the costs of returning it to its original condition.

emma lunn

Emma Lunn

Money Writer

Emma Lunn is a multi-award winning journalist who specialises in personal finance and consumer issues. 

With more than 18 years’ experience in personal finance, Emma has covered topics including mortgages, first-time buyers, leasehold, banking, debt, budgeting, broadband, energy, pensions and investments. 

Emma’s one of the most prolific freelance personal finance journalists with a back catalogue of work in newspapers such as The Guardian, The Independent, The Daily Telegraph, the Mail on Sunday, and the Mirror. 

As a freelancer she has also completed various in-house contracts at The Guardian, The Independent, Mortgage Solutions, Orange, and Moneywise. She also writes regularly for specialist magazines and websites such as Property Hub, Mortgage Strategy and 

She has a real passion for helping people learn about money – especially when many people are struggling to get by in today’s challenging economic climate – and prides herself on simplifying complex subjects.

Molly Dyson


After growing up with a passion for writing, Molly studied journalism and creative writing at university in her home country of the United States.

She has written for a variety of print and online publications, from small town newspapers to international magazines. Most of her 10-year career since relocating to the UK has been spent in business journalism, writing and editing for admin professionals at PA Life magazine and business travel managers at Business Travel News Europe and representing those titles at conferences around the world.

Now an Editor at the Independent Advisor, Molly is an expert in a broad range of consumer topics, that include solar panels and renewables, home improvements and home insurance, and consumer technology such as home security and VPNs.

In her free time, Molly can usually be found exploring the outdoors with her husband and their young son or gardening.