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What Is ECU Remapping and Should You Remap Your Car/Van Engine?

I am interested in cars and do my own repairs where I can. I like to share any knowledge I have to help other people where possible.

Are my eyes going funny or are we going really faaaaaaaast?

Are my eyes going funny or are we going really faaaaaaaast?

Having your car or van engine remapped, also known as chipping, is a way to get more power out of your car or van engine. This article will explain exactly what it is and will help you to make up your mind as to whether it's something that could benefit you!

Remapping/Tuning/Chipping—What Is It?

All of these terms are used to describe the same thing. Modern car and van engines have an electronic management system that controls fuelling. This system is run by the brain of the engine, the ECU (Engine Control Unit). When you put your foot down, the ECU decides how much fuel and air to mix, squirt into the cylinder and ignite. Diesel and petrol engines work a bit differently, but that isn't really important right now. The ECU also controls the boost of the turbo (if you have one).

If you have your engine remapped/chipped/chip tuned, then the ECU parameters can be changed, giving more performance—in certain cases more economy—from your engine.

How Do You Remap Your Engine?

This is done in several different ways. The most common is to connect to the vehicle diagnostic port and reflash the software on the ECU, with a standard map for the vehicle in question. This does need special equipment. Since it's all done with software, a new map can be uploaded to your vehicle ECU pretty quickly and can often be completed in less than an hour.

The second way, which will get you better results but costs more, is to have a custom remap for your vehicle. The car or van is connected to a laptop, but instead of uploading a one-size-fits-all remap, the parameters for your individual vehicle can be altered. This is usually combined with runs on a dynamometer, so your vehicle's performance and fuelling is checked and tweaked all the way through the rev range.

It is also possible a piggyback device that attaches to the ECU with some vehicles. There are lots of devices on the market. A lot of them are very cheap and you can often fit them yourself, but usually, they just make the vehicle run richer and aren't really any use. Getting your car or van remapped with someone who knows what they're doing and will do it properly is generally a better option, even if it costs more.

If It's That Easy, Why Don't the Manufacturers Do It?

This is a common question. There are several reasons that manufacturers don't supply the car or van already maximised as far as performance and economy go.

The first is that manufacturers focus mainly on reliability. Some people look after their cars, regularly servicing them and taking good care of them. Some don't do anything other than put fuel in. There are also different grades of fuel, depending on where you are.

In an ideal world, everybody would look after their car and fuel would be good quality everywhere you go. Since this isn't the world we live in, then if manufacturers err on the side of safety and supply their vehicle at a less than optimal tune, then there's a higher chance of it lasting longer. This means that the manufacturer gets a reputation for reliability as their cars are less likely to break down. If you are prepared to service your car, look after it a bit, and also use good fuel, then having the engine remapped won't be an issue.

The other issue is that manufacturers often have a range of vehicles, and the most powerful vehicles in the range are usually the most expensive. Manufacturers often stifle the performance of engines to make sure there is a clear difference in power as you step up the range. In some cases, you can buy a cheaper version of the car or van and then remap it to equal or beat the next model in the range.


Extra Performance? But I'm Not a Speed Racer . . .

While there is extra performance available from the engine, this isn't the only benefit. As long as you're willing to drive normally, then you can also get an increase in MPG. It depends on the vehicle, but some people report up to 5 MPG more after remapping, so if you do enough miles then you can recoup the money that the remap costs. You have to remember that a heavy right foot will still use fuel, whether it's remapped or not!

The other thing is that if you have a van and carry heavy loads, then sometimes a remap can really help the driveability of the vehicle, giving you more oomph so you can zoom rather than crawl up hills.

Should I Get My Car/Van Remapped?

There are several things you need to bear in mind when thinking about getting your car or van remapped.

The first thing is to think about what sort of an engine you have in there. The best gains can usually be had from turbocharged vehicles, both petrol or diesel. Remapping these can lead to big performance gains as the boost from the turbo can be increased. Naturally aspirated (NA) engines will not give you the same performance gains. If you are running a small NA engine, then remapping may increase the drivability and give you a small performance boost, but you'll have to weigh up the cost and think about whether a small increase in performance will be worth the money. The larger and more powerful the engine is in the first place, the more gains you'll get from remapping.

Extra performance is not the only thing you can get from a remap. The economy of the car can often be increased as well, but this depends on how the car is driven. In an ideal world, you won't drive any faster than before and you'll see better fuel economy. Of course what tends to happen is that you have more performance from the remap, so you use the extra performance and end up using more fuel than before. Once you get used to the power and start driving normally again, you'll see better economy. It is also possible to get a remap that is specifically designed to increase economy. Performance is compromised at the cost of economy with these sort of maps, but this is something some people, cab drivers, for example, are happy since they don't care about performance and just want more MPG.


Making the Most of Your Remapped Engine

If you have a petrol car remapped, then you might find that you need to run the car on premium, high-octane fuel to stop engine pre-detonation, which can damage the engine. In my opinion, the increased cost of premium fuel is not a problem if the engine is providing more performance, but this may matter to some people so this is something else to bear in mind. Not all remaps necessitate the use of premium fuel, so you should ask the person that is remapping your vehicle just to ensure that you don't cause any damage.

If your vehicle is remapped, then you can sometimes find that the increased power can hasten the demise of your clutch. If your clutch is healthy, then you should be fine, but if it's near the end of its life, then a remap can help speed it on its way.

Do Your Research Before Remapping!

There isn't much point having a remap unless everything else is in good condition, so it's a good idea to get your vehicle checked over first before you go ahead with the remap. You also need to bear in mind that your insurance company should be told about the remap, which might lead to an increase in your premium.

So there you go—a brief explanation of remapping. Many people feel it is a worthwhile procedure, but you'll have to weigh the pros and cons for yourself. Hopefully, you understand it a little better now.

If you have any questions or comments, please leave them below. Thanks for reading!

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2012 Rain Defence


Tina birch on August 14, 2019:

If you have a remap but have to change the engine does it need to be remaped or taken back to original settings

N/A on May 31, 2019:

And here's the cop suckers.... Nobody gives a crap whether it's illegal or not. And it's common since warranty will void.... Some of us don't like our vehicles governed.

Sparky on February 09, 2019:

Its not a question of should you. It is a violation of Federal Law and Manufacturers laws. If you do not care about a warranty and have lots of $$$ in the bank, then hp ahead and mod/re-tune it. Just understand you will not be able to skate by the dealer for warranty work anymore.

Mike on January 05, 2019:

Just remember this will void powertrain/engine warranty. It is illegal, against manufacture law and Federal laws.

Travis on March 11, 2018:


I would think they offered you a warranty with the car. If the car has been tuned, it is at a greater risk of breaking down.

Arber on February 27, 2018:

Hey i just bought a 2014 Cadillac ATS and my dealer just found out it was tuned by the previous owner and wont let me drive it. They are bringing it to Cadillac to detune it next Thursday. The car has 59,000 miles. And it takes premium gas. Why are they saying i cant drive and should i allow them to detune it? Thanks

Alfred T on February 11, 2018:

Hi, just to add some confidence to prospective up grader.

Had a 1998 Porsche 996 which was remapped by previous owner and enjoyed driving it....lent it to a friend and he "total" it!

Subsequently bought a 2000 one which is standard original but just didn't feel the same!

Engaged a professional who had to email Porsche factory with my engine serial number for a one off (chargeable) ECU mapping program to download to my car.

After tuning still didn't achieve the desired performance so I was advices to also upgrade the MAF and ..... ooh la la I'm flying again !!!

PETER ROSE on January 17, 2018:

Anyone in Vancouver Canada doing remapping? jaguar X series

D on November 22, 2017:

Thanks a bunch for the info. This idea is something that has crossed my mind but never knew it was actually being done already. In this day and age of better consumers, and a world with ever-dwindling resources, the manufacturers perspective and progress are simply and painfully lagging, in my humble opinion.

MIKE ONG on October 18, 2017:

I own a honda CRV year of make 2005 the pick-up and top speed is very limited wishes to know by remapping my vehicle will boost the horsepower n top speed.Further to that will it cause any problems later tq awaiting your reply.

Andrew on October 16, 2017:

What a great article. Thanks for the information

Travis on November 17, 2016:

@collin I imagine Canada works similarly to the US in that the degree of enforceability is a bigger factor than the legality. For example, making modifications to your vehicle that put it out of emissions tolerances is illegal. Yet it is undetectable until annual or bi annual emissions testing. An engine remap on the other hand doesn't really affect the emissions issue and I cant understand why chipping is illegal in Canada. Unless engine mods are explicitly forbidden; what's the difference in installing forged pistons?. Please enlighten!

Zeeshan on October 11, 2016:

Yes there is for volvo if you get it done by polestar then its legal

Collin on August 17, 2016:

Is remapping your car legal to a degree in Ontario, Canada?

Generally adding performance chips in cars in Ontario is very illegal and it can get you in a lot of poop if the wrong people find out, is there a way to legally remap your car?

Tonytmb on August 09, 2016:

Vivaro 1.9 cdti 54 plate will not rev above 4000rpm will not start with out easystart then will tick over great plz help

Chris Mills from Traverse City, MI on December 07, 2015:

I found your article on a site called Encyclopedial.com today. I wanted to let you know. The URL of your article is http://encyclopedial.com/2015/12/07/what-is-ecu-re...

Rain Defence (author) from UK on August 08, 2015:

As long as your car is in good shape there's no reason why that would happen.

Rain Defence (author) from UK on August 08, 2015:

To be honest I wouldn't bother. You get the best results from turbocharged engines or large naturally aspirated ones. A small naturally aspirated engine wouldn't really give much of an improvement if mapped. I'd just buy a car with a bigger engine!

sean on February 27, 2015:

got a 13 plate corsa 1.2. its got no power whatsoever and fuel efficiency not great either. been told if I get it remapped it will increase power and fuel efficiency . is it a good idea?

Craig on February 26, 2015:

Could it make my car over heat

Rob white on October 26, 2014:

Hi there awesome article btw extremely enlightening and reassuring, I have a question for you. Iv got a vw transporter 2011 it's the new 2.0 litre version (the facelift version) 5 speed gearbox 102bhp model, Iv been looking into getting it remapped professionally with a custom map however my one concern is Iv heard horror story's of drive shafts tearing loose and gearboxes being destroyed!

I'll add that this is all hearsay from various mechanics Iv spoken to and I have no actual first hand experiences so can't really comment, however after driving my friends slightly older t5 which he just had remapped it really is clear the engine on mine needs waking up!!! So I guess my question is should I be worried about damaging things like the drive shaft clutch gearbox injectors turbo etc etc etc (which as I'm sure you're aware are all things that are extremely expensive on a vw!) or is that just a pessimistic view on it? Bearing in mind I carry lots of tools around regularly this van being my biggest one! which I saved up a long time to pay for and want to keep well maintained so it can hopefully see me through my working life, it's just so sluggish going up long hills etc and the extra power

(if safe) would be a god send!

Thanks for reading, regards rob

Tom Barr from Crewkerne on January 29, 2014:

Hi I have had the same problem jrw2608 with my remap cutting in and out. . If it was the maf wouldn't the engine light come on? Did you find out if it was the maf? As this problem is bugging me. . Many thanks

Rain Defence (author) from UK on September 30, 2013:

Ok, keep me posted!

jrw2608 on September 30, 2013:

Well I will take your advice

And do that

I am



With mechanics , and really grate full for the direction,


Let you know

Rain Defence (author) from UK on September 30, 2013:

I would say its far more likely to be the maf than the ecu to be honest but of course I can't say for certain. If you can get a new maf for £30 then in your shoes I'd fit that. If it doesn't solve the problem at least you've ruled it out. If it sorts it, it's £30 well spent.

jrw2608 on September 30, 2013:

Hi been giving your comment about ecu some thought !

Apart from the no pick up revs sometimes After starting, which by the way is getting more frequent.

I have developed another problem , some times now when gear down to 3rd/2nd to turn corner the can may cut

Out !!

Would this be more to ecu or


Also got some prices on a maf £90 from limes of apd/motor quip, yet I see on eBay new one for £30 haven't even fried Reno yet. Does that sound right

Any help would be great

Rain Defence (author) from UK on October 11, 2012:

Insurance costs can increase a little, but not by much. Some people choose not to tell their insurance companies, but I can't condone that course of action.

dommcg on October 11, 2012:

Some great info here, does remapping increase your insurance costs?

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