ECU Remapping FAQ’s

Whilst a remap will add a small amount of extra strain to the vehicle, all of our files are well within the safe parameters of the vehicle’s components (such as the engine & transmission/drivetrain) capabilities. We would only increase engine output to what we deem to be safe as it wouldn’t be beneficial to us or you to push your vehicle to anything beyond that.

It is not in our interest to push your vehicle past its limits. We simply wouldn’t have a business if we blew cars up on a daily basis.

With that said, it is your responsibility to ensure your vehicle is in correct working order, has had parts changed as per the MANUFCATURERS RECOMMENDATIONS (such as spark plugs being changed when they’re meant to).

It’s worth noting, a lot of our customers claim their vehicle has ‘full service history’ when they may have just had an oil change every year. This is not servicing as per the manufacturers spec. 

One of the most common issues we see on petrol vehicles (Although issues are rare, perhaps 1 in 500) is spark plugs being at the end of their life, causing misfires post-tune.

In almost 100% of cases, issues with a vehicle after a tune are not tune related but are component related.

Misfires due to faulty spark plugs or coil packs and boost leaks are the most common issues we see post-tune – this is always due to poor maintenance.

There are a couple of ways for a remap to be detected. The most cost effective and most commonly used method by manufacturers is to check the CVN with diagnostics tools. If an ECU has a different CVN than it should, a manufacturer’s diagnostic tools will be able to detect this.

A remap can also be detected with manipulation DTC’s that appear within various modules in the car.

Some dealer tools can detect that changes have been made to the original software but don’t show exactly what has been done.

With most modern vehicles, our industry-leading remapping software and tools can successfully flash an ECU whilst keeping the original CVN and not throwing any manipulation DTC’s. This means most dealer diagnostic tools would not be able to detect the remap.

That said, a remap is NEVER undetectable. If someone wants to dig deep enough, they will eventually find it.

A good workaround for this which covers most instances is to have the vehicle returned to stock which we are able to do for £60 including VAT.

Depending on the method of tuning for your particular car, we can mitigate the chances of it being detected.

If you’re after JUST a pop and bang or JUST an EGR solution, we do offer this at a slightly cheaper rate than we would if we were also tuning the vehicle.

To obtain a quote or to book this in, enter your reg on our reg checker and select ‘other services’.

A very common question with very common misconceptions. Ultimately, there is no such thing as a generic map. ‘Generic’ implies that we could use any tune file on any vehicle. Every tune we apply has been custom calibrated for your vehicle make, model, drivetrain, ECU and software version.

For stage 1 and most stage 2 files, we can use dyno tested, safe and proven solutions without having to make any tweaks. Why? Because we know it’s a safe calibration that we’ve used before on an identical drivetrain that’s been developed on the dyno and on the road.

We can apply calibrations at our Surreyshire branch for heavily modified vehicles with the use of our rolling road.

There is a common misconception that a tune made ‘on the fly’ is both much safer and will produce better results. This isn’t necessarily the case, the quality of the tune is down to the tuners ability to tune on a particular platform of drivetrain and ECU combination.

There is no tuner in the world that writes completely custom software from scratch every time. In most instances, they’ll either use a tried and tested solution OR use that solution as a base to work from and apply very minor tweaks. However, these tweaks will only be made if a car has heavy modifications.

The only time this differs slightly is for heavily modified vehicles, i.e. uprated fueling, uprated turbos etc. In this instance, a heavily modified car will likely have a unique combination of modifications. What usually happens is the tuner will, again, apply a base map from a tried and tested solution and then modify that calibration with a few revisions to suit the modifications.

What you need to be looking out for is not the ‘custom vs. generic’ argument at all. You should be looking out for companies that offer remapping but use clone tools (which have a high likelihood of killing the ECU) and apply untested £1.00 calibrations from a CD they bought on eBay.

A good way to be sure you’re talking to a good tuner is to look at their reviews, digital presence and importantly, how much they’re charging. If they’re only charging £150 for a remap, the chances are they don’t have the funds to afford insurance or to pay to fix the car if it goes wrong and their general costs to carry out work are low, thus leaving you with something of poor quality.


There’s no such thing as a generic map. Don’t cheap out. Choose your tuning company based on reviews, presence and trust.

This is always a tough question. The reality is, modifying your vehicle will always affect a manufacturers’ warranty. Whether the manufacturer rejects a warranty claim is down to their discretion.

Bear in mind we can always flash your vehicle to stock for £60 including VAT.

At our Surrey branch, we are able to provide customised calibrations for heavily modified vehicles with the use of our rolling road. You can also request before and after dyno runs when booking online or you can opt for a custom tuning session if your vehicle is heavily modified.

In general, at Phantom Tuning, we mainly cover stage 1 and stage 2 ECU remapping.

When it comes to relatively basic requirements such as stage 1 and stage 2 remapping, a dyno is not always needed. The reason for this is our software has already been tested on a dyno where a slave or donor vehicle was remapped during our research and development process.

This means that we’ve already stress tested and proven the figures that our remaps can provide on a well-maintained vehicle.

For stage 1, the donor vehicle is identical to yours, so there is no need to dyno test the file again. For stage 2, the need for a dyno depends on whether or not there are any discrepancies in modifications.

This means that we’ve already stress tested and proven the figures that our remaps can provide on a well-maintained vehicle. For stage 1, the donor vehicle is identical to yours, so there is no need to dyno test the file again. For stage 2, the need for a dyno depends on whether or not there are any discrepancies in modifications.

As part of our service, in most cases, we will road test a vehicle when possible, to ensure the vehicle behaves as intended.

To summarise, there is absolutely no need to run a car on our dyno in order to provide you with a high-quality tune UNLESS your vehicle has upgraded turbos or fuel delivery.

We do not guarantee any fuel economy improvements due to external factors that are out of our control.

Whilst we can tune a vehicle to be more economical, if you have lower than normal tyre pressures, use different fuel than normal or drive with a heavier foot than normal (amongst other things), you may lose fuel economy.

In most cases, a majority of our customers report either a slight improvement of another 1 or 2 to the gallon OR it stays the same.

Some companies will quote up to 20% guaranteed fuel economy savings and this just isn’t realistic. 

If you’re looking to tune your car purely for economy and aren’t bothered about performance improvements, don’t tune your car.

Manufacturers restrict the performance of a vehicle for multiple reasons. An example would be warranty lifespan. It’s in a manufacturer’s interest to ensure their vehicles underperform to reduce the number of warranty claims during the warranty period. It also enables them to extend the time and mileage in which a warranty can be offered. Increasingly now, manufacturers are saving costs by limiting the number of engine sizes they offer and instead of developing lots of different engines, they’re using different powered versions of the same engine. This enables them to not only save money on research and development but also to charge more money for a vehicle with a higher power output.

For example, the Ford Transit Custom is available in: 100BHP, 125BHP and 150BHP. However, each of them uses the same engine, transmission and drivetrain. The interesting thing is that each of the versions are capable of 180BHP. They simply charge more for the higher-powered versions.

Manufacturers also need to bear in mind that their vehicles are being sold across the globe with various tax brackets, insurance groups and environmental conditions. As a result, they need one universal map to suit all scenarios whilst ensuring maximum sales of the vehicle in question.

Nothing. Typically, all that the different driving modes tend to do is change your throttle mapping. Some vehicles also add weight to your steering and tighten the suspension.

With a tune, the power is changed across all modes. your existing modes will still behave the same and each mode will have its own custom throttle calibration.

This is possible for some cars but it is ultimately pointless in most cases.

Some argue ‘I only want the map in sport mode and I’ll drive in comfort with the map off to save fuel’. Well, in theory, a remap should either improve economy or it will stay the same. So why would you want less power output if there was no benefit?

In reality, whenever we have applied tunes to just a sport mode, the customer has always returned and had to pay for us to reapply the tune in all modes.

The only time that this tends to differ is when it comes to high power output vehicles with very heavy modifications. We would typically have multimap available in various modes in the car that enables us to apply different levels of boost and power.

We do. Stage 2 requirements are: upgraded intake & decatted or sports catted downpipes. We currently do not offer any fitting services so these modifications would need to be done prior to arrival.

For figures on stage 2, an average car will gain an extra 15-30bhp and 20-40nm over a stage 1 tune, depending on the vehicle. 

The calibrations for stage 1 and 2 are quite similar, however, most of the additional gains will come from the physical modifications rather than the tune itself. For example, if you’re already running a stage 1 tune and have already applied stage 2 modifications, it’s unlikely that you’ll feel too much difference in changing the map to a stage 2. 

If we have stage 2 figures tested on our dyno, you’ll see the figures on the results page of our reg checker. If we cannot supply gains, bear in mind the rule above to get an idea on figures.

If your vehicle goes in for service work at a main dealer and it’s in warranty, we would advise you to bring the vehicle to us first to remove the map and then come back to reapply the tune.

If your vehicle isn’t in warranty or you’re not visiting a main dealer, you don’t have to worry about taking the map off and reapplying.

However, if you do have your car serviced at a main dealer, whether it is in warranty or not, they may need to apply a software update to your vehicle. In this event, there is a chance you may lose your map. If you do, we can reflash the modified file on to your car for a small fee of £120 inc. VAT.

In short, no. A remap wouldn’t disappear anyway; the whole flash data would disappear, but again, this is impossible on its own accord. If it were to happen, your car wouldn’t start! The only way you can lose your tune is if the vehicle is flashed to stock by another tuner or main dealer via software update.

There exists a rumour that disconnecting your battery will wipe your remap. This is just a rumour, your tune would still remain. If you were to take your battery out of your laptop and replace it, it wouldn’t automatically restore factory software. The same applies to your ECU. There is no way to hit the ‘reset button’ on an ECU without third party tools.

Unfortunately, components fail on stock and tuned vehicles. Whether it be a broken coil pack, blown turbo or cracked block. These things can happen and parts don’t last forever. Ultimately, we won’t tune a handful of vehicles because they are prone to specific failures post-tune. However, if your vehicle has an issue post tune, it’s likely that said issue was already present or on its way to being an issue before it was remapped. Our advice is to take it to a trusted mechanic to carry out diagnostics and to help you rectify the issue. In a worst case scenario, we are able to flash the vehicle back to stock for £60 including VAT to help diagnose the fault. Out of the thousands of vehicles we have tuned, we are yet to see a failure due solely to the car being remapped.

Whether your car is tuned or stock, the only way to determine these figures is to run the car on a dynamometer (AKA Dyno or Rolling Road). If you have not opted to pay for our dyno services in our HQ at Surreyshire, we will not be able to tell you the exact figures for your vehicle. We can only tell you what an identical drivetrain, running stock power produced with the same remap. You’re always welcome to come back to us for a dyno run, power runs on their own are £100 including VAT.

If you’re after more power once you’ve had a stage 1 tune or ECU Remap, you’ll need to start making physical modifications to the drivetrain. Breathing mods such as intake and exhaust can add anywhere from 15-30bhp, after that, you’ll need to start considering turbo upgrades and more. Your best bet is to do some research in your vehicle’s community to figure out how much you’re willing to spend to make certain power figures. Once these modifications are installed, we can write custom calibrated tunes to suit your vehicle’s needs.

Whilst we love to see people carrying out more frequent servicing, for mild tuning, there’s no need to service any more than the manufacturer’s recommended schedule. Doing so will only help increase your engine’s longevity but it is not mandatory.

If your vehicle fails an MOT after being tuned, the remap is not the issue, you have a mechanical fault somewhere (likely with the emissions systems).

You must always inform your insurer of any vehicle modifications, including an ECU remap.

As mentioned previously, the only way to have ‘lost a remap’ is if the vehicle has been flashed with new software via a main dealer tool or by another tuner. If this hasn’t occurred, you haven’t lost your remap. Whilst we can check that your tune is still there for £60 including VAT, unless you’ve been told that your vehicle has been flashed, we’d advise not paying for this service. If the vehicle has been flashed to stock and you pay £60 including VAT for us to check, we can reapply the tune at no additional cost as long as it is running the same software version. If the vehicle is running a different software version, we will charge £120 including VAT.

Unfortunately, we see a large number of mechanics run into issues with cars that they simply do not have the knowledge or tools to diagnose. It’s easy for a mechanic, with limited knowledge of how tuning works, to charge customers a few hundred quid for diagnostic services, not be able to determine the issue and blame a remap. Effectively, it’s their way of using a ‘get out of jail free’ card when they’re out of their depth.

Time and time again, we flash vehicles back to stock, at the expense of the customer, for the issue to still be present. Time and time again, although we are not mechanics and do not claim to be, we end up carry out datalogging sessions and diagnostics to help our customers ascertain the issue, get it right and there was never an issue with the tune in the first place.

We’ve heard plenty of stories such as ‘my mechanic has changes all the injectors, spark plugs and coil packs and I’ve spent over £1000 trying to solve the issue so it must be the remap.’ We then do some data logging, use basic logic and trouble finding to determine the fault was an inexpensive fix such as a wiring fault.

If there is an issue with the remap, the issue will be immediately present. It won’t develop days, weeks or months later. With that said, if there is an issue immediately after tuning, this doesn’t mean it’s an issue with the tune, necessarily. In almost all cases, there was a part or component that was close to failure prior to tuning.

Remember, with the tune that we are applying to your vehicle, we have likely used that exact same calibration a handful of times before and if there was an issue with the remap, we would have all customers with the same calibration complaining of the same faults.

Due to our experience with a lot of ‘my mechanic said this’ stories, we would always advise that you DO NOT tell your mechanic that your vehicle is tuned when they are diagnosing a fault with your car.