Is Remapping a Car Legal in the UK?

Remapping your car is an effective way to improve your car’s performance and fuel economy. 

But, is remapping a car legal in the UK?

Let’s find out.

What Does Remapping a Car Mean?

Remapping a car, also called ‘chipping,’ is a quick and cost-effective process that allows you to change or upgrade the microchip in your car’s ECU (Engine Control Unit) and essentially overwrite the manufacturer’s factory settings to allow the car to function at full potential. 

By remapping the software and fine-tuning the engine, the car’s maximum performance can increase by up to 35%.

But why do ECUs limit the performance capabilities of cars in the first place? 

Manufacturers have plenty of reasons to impose certain restrictions: regulation of noise and emissions, adapting the car to the country’s climate, and terrain and fuel quality (to lengthen the car’s lifespan).

Is Remapping a Car Legal in the UK?

There is no current law that prevents Brits from remapping their cars. 

Geeky car enthusiasts do it all by themselves (some even write their own code), but if you’re not an expert, it’s best to drop off your car at a garage because a mistake can be expensive.

Pros and Cons of Remapping a Car

Remapping a car can bring some beneficial changes to your car’s overall performance, for example:

• More speed and power: The car won’t have to work as hard as it did before when accelerating, climbing, or towing a heavy trailer or a caravan. 
• Better fuel economy: Remapping an engine increases the car’s mpg(mile per gallon), but only if you adjust your driving.
• Better driveability: Chipping your car will give it a better engine response and an enhanced throttle, which will allow for a smoother ride.

While there are some positive aspects to enhancing the car’s capabilities, there are some downsides to modifying the ECU.

Some of the disadvantages of mapping a car include: 

• It’s beneficial for certain engines: A non-turbo petrol model will benefit little in brake horsepower.
• Reduced engine’s lifespan: The extra power that comes from remapping puts more strain on the engine. It also means that certain components like the clutch will wear out faster and the car will require more regular service checkups than before.
• It can invalidate your car’s warranty: if a remap isn’t approved by the manufacturer or the dealership where you purchased it, it may invalidate the warranty agreement.

How much does it cost to remap a car in the UK?

The car remapping cost depends entirely on the car’s model.

Some simple engine remaps are around £150 (VAT not included). In most cases, remapping will cost between £200 and £400, unless you opt for a car map switch, which will cost more.

Still, the car remap cost can go past £400 for some newer models or vehicles that require bigger engine remaps.

Is remapping a car safe?

Car remaps are generally safe when done by professionals. 

However, not all cars are good candidates for remapping. 

Adding a chip to the computer controls will further increase the risk of damage if your car has a poor service history or if the car has been driven a lot (since the remap will increase wear and tear of components and can potentially worsen the car’s condition).

Does engine remapping affect insurance?

If you remap your car, you need to inform your insurance company about the changes because some insurance companies don’t cover vehicle remapping (in which case you can find a remap specialist insurance provider and reach a finance agreement).

if your insurance provider does and you get your car remapped, they will increase your premiums, but you will have remapped car insurance. 

However, failing to inform your insurance provider, will invalidate your policy agreement. 

In addition to affecting your insurance policy, a remap will also void your warranty since the change puts more pressure on your car components, such as the  engine, turbo, gearbox, clutch, flywheel, and other electronics,

Does remapping affect MOT?

The MOT (Missionary of Transport) is an annual test required in the United Kingdom for most vehicles over three years old. The test checks the vehicle’s safety, roadworthiness, drivability, and exhaust emissions. 

If you like to learn more about what happens at an MOT test and what would happened if you accidentally drive without one, take a look at this article.

Your car is unlikely to fail an MOT test after a remap unless the fuelling affects emissions.

Bottom Line 

Engine remapping was once a preserve of car enthusiasts but has gone mainstream in the last several years. Remapping the ECU of your car is often quick, cheap, and effective, but it does come with some consequences, like pricier insurance premiums and the faster wear and tear of car components.

Ultimately, whether it’s a good option or not depends on your primary goal and whether the risk is worth it.