Frequently Asked Questions

Please check our list of Frequently asked questions for an answer. If your question is not answered here please don't hesitate to give us a call on +44 (0)1246 455004 and we will be more than happy to help you.

What is Custom-Code Performance Software?

In layman’s terms, installing Custom-Code software involves recalibrating your vehicle’s ECU (Engine Electronic Control Unit) to provide you with more power and torque from the exact same components. Likewise with DSG (Direct Shift Gearbox) Software, except you see the benefits in launch RPM, increased torque limit, shift response and disabling of automatic shifting.

Why would I want Custom-Code Software?

A Custom-Code remap will provide you with the following:

- Increased power

- Increased torque

- Eliminate flat spots in your vehicle’s rev range

- Increased fuel economy

- Faster ¼ mile speed

Why isn't the ECU "remapped" by the manufacturer originally?

Firstly fuel quality can vary greatly from country to country, and due to the wide span of the markets that vehicles are usually sold in, the manufacturer has to cater for a range of available octane fuels. The fuel quality in the UK is much better than in most countries, so Custom-Code software can really unlock that extra potential within your engine.

Secondly manufacturers like to build cars that perform well across many different nations, and therefore many different climates. The ambient temperature the engine is working in might be +30° or -30°, and it has to output the same power in both these conditions. This leads to the manufacturer purposefully building in a buffer zone to enable the engine to perform the same everywhere. Once again, using Custom-Code software will allow you to get more out of your engine.

How can I get lower fuel consumption as well as better performance from my vehicle?

Today’s fuel costs are ever increasing, but you still want to enjoy your driving experience. With Custom-Code Software installed, there really is no need to compromise. If you do a lot of long distance driving Custom-Code software can pay for itself in months! Custom-Code carefully matches increases in turbo boost pressure with the remapped ignition timing and fuelling. It doesn’t affect reliability or the life of the engine.

Every Custom-Code remap delivers:

- An engine that responds more eagerly to your right foot

- Smoother power delivery making town driving much easier with fewer gear changes

- Improved acceleration for safer overtaking

For non-turbo petrol cars:

- Up to 10% more power

- Enhanced throttle response

For turbocharged petrol cars:

- Up to 20% more power

- Up to 25% more midrange torque

For turbo-diesel cars:

- Up to 30% more torque and more power

- Fuel economy improvements

With a remapped ECU, your car will produce more power which means you can reach your target speed much quicker. The most economical way to drive is to reach your target speed quickly and switch to a high gear for economy. Furthermore the software can be tuned specifically to provide better MPG by altering the fuelling and timing.

How do I get Custom-Code Software for my vehicle?

There are a number of ways to get Custom-Code on your vehicle:

- Purchase a Flashwire and flash your software from the comfort of your own home

- Book in and visit Custom-Code HQ

- Visit one of Custom-Code’s authorised dealers

- Send your ECU to us via post

How do I ship my ECU to Custom-Code?

ECU’s are fairly robust, we suggest wrapping your ECU in bubble wrap and putting it in a sturdy cardboard box. Once packaged make sure you send the package via INSURED UPS or Fed-Ex who we have found to be extremely reliable.

How long will it take to install?

Installation normally takes between 1 and 3 hours depending on your particular vehicle. We would first visually inspect your vehicle, then test drive it and check with diagnostic equipment for any previous faults, The vehicle is then flashed via the OBD port and then data logged and setup. This may be longer for certain vehicles, please call us to check.

Will Custom-Code Software invalidate my manufacturer's warranty?

The Dealership and/or vehicle manufacturer must prove that the part that you are trying to get covered under warranty failed as a DIRECT result of Custom-Code Software. Please refer to the Mag-Moss Act for more information regarding this law.

What is the upgrade policy?

Custom Code believes in rewarding customer loyalty, so we offer a unique upgrade program. If you have bought a Phase One Remap, you can upgrade to Phase Two (on the same vehicle) at any time and receive a 40% discount. Likewise, any customer who has purchased a Phase Two Remap can upgrade to Phase Three (on the same vehicle) and receive a 33% discount.

What guarantee does Custom-Code give your ECU remap?

We’re so confident that you’ll love our software that we offer a 30 day satisfaction guarantee. That means if you’re not satisfied for whatever reason we’ll happily refund you in full within the first 30 days of purchase.

How do I find out about new versions or upgrades of Custom-Code Software?

New software versions are periodically released by the original manufacturer, to which Custom-Code respond quickly with new versions of their own Software. Custom-Code is always based on the very latest version of the factory software, keeping us ahead of the game in terms of development.

If you'd like more information regarding this please call the Custom-Code support team on +44 (0)1246 455004

Will installing Custom-Code Software affect my insurance?

Most likely, yes. This will mostly depend on your individual circumstances, however some insurers will leave your premium unchanged. It might be an idea to check with your insurer and canvas other insurance companies for quotes before booking in to have Custom-Code Software installed, just to make sure it is still within your budget.

Can Custom-Code Software be detected by my Authorised Dealer?

An experienced technician that knows what he or she is looking at will be able to determine if your vehicle’s ECU is modified. However if you purchase our Flashwire, you can flash the ECU back to the original OEM stock before it heads back to the authorised dealer.

How do I find my ECU part number (ECU ID)?

There are multiple ways to receive your ECU Part Number (commonly referred to as your “ECU ID” by Custom-Code).

1) VAG-COM/VCDS cable

2) Removing the ECU and reading the Part Number on the top cover

3) Visit an Authorized Custom-Code Dealer

If you have a Ross-Tech VAG-COM Cable and VCDS, you are able to retrieve the ECU ID with these tools, without the need to visit Custom-Code or an Authorized Custom-Code Dealer. We’re going to assume you are aware of how to connect your VAG-COM cable to your computer and to the vehicle’s OBD-II port. We’ll also assume that you’ve already configured your VCDS application to work with your VAG-COM cable. If you are having difficulty with any of the two above, please visit Ross-Tech’s website at

1) Click ‘SELECT” in the VCDS application

2) Select ’01-Engine’

3) The ECU ID and ECU Revision Number are populated once the controller data is retrieved from the ECU.

What is an OBD-II (or OBD-2) Port?

OBD-II stands for On Board Diagnostics II, which is the second iteration of the OBD systems, which was made mandatory equipment in all new vehicles starting in 1996. Prior to OBD-II, vehicles were equipped with OBD-I systems.

Can all ECUs be flashed via the OBD-II Port?

No, not all ECU types can be flashed via the OBD-II port. Bosch Motronic MED17, EDC17, and Siemens SIMOS 8 ECUs found in the latest generations of Volkswagen, Audi, Porsche, Seat, and Skoda vehicles cannot be flashed via the OBD-II port upon initial installation. These ECUs require to be removed and flashed on the bench using Custom-Code Boot Pin flashing equipment.

This procedure is roughly a 2-hour process and can be done at any Authorized Custom-Code Dealer or Custom-Code HQ. After the MED17 ECU has been removed and flashed with Software, future updates or upgrades can be performed via the OBD-II port.

Can I see a Dyno Graph to prove the power output?

If you wish we can run your car on our in-house dyno to show you the quantifiable results that can be achieved with our software, alternatively we can show you an example graph of your car from one of the many we have previously remapped. You can access these maps from the specific remap page for your model of vehicle, or find your engine in the Rolling Road Data section of our media page.

Does Custom-Code Software adapt to different Octane fuel?

Bosch Motronic ECUs do have the ability to adapt to different octane fuels. However, if you are running Custom-Code Software that requires a minimum of 95-octane fuel, that fuel grade should always be used. In the event that you find yourself in an extreme situation, you are able to use your own discretion to determine if using a lower grade fuel TEMPORARILY is sufficient. In most cases, if you cannot locate 95 octane, 91 or 93 octane can be used TEMPORARILY and sparingly until you are able to acquire 95 octane or higher. Please call us on +44 (0)1246 455 004 if you require further information regarding fuel quality.

At what stage is the DSG Software mandatory?

The DSG’s torque limiter is set at 350NM, therefore, beyond that level, you will begin to notice some abnormal reactions, clutch engagement, and shift patterns.

Custom-Code’s DSG software is recommended after you reach or exceed 350NM/260LB-FT TQ, although DSG Performance Software is suitable for all levels whether complete stock, Phase 1, Phase 2 or Phase 3.

Should service intervals be reduced when running Custom-Code Software?

For Phase 1 software, no. However for Phase 2 and 3 software we suggest reducing service intervals by 10-20%.

What if my Authorised Dealer performs a factory software update to my ECU?

Sometimes your dealership will update your ECU with the latest software update from the manufacturer, if this happens don’t worry, Custom-Code have you covered. Just give your local Custom-Code dealer a call and they will re-flash your Custom-Code software product back onto your ECU for you. If you have purchased one of our FlashWire devices, you can perform this action yourself at home.

NOTE: Authorized Custom-Code Dealers reserve the right to charge for their time (labour) on reflashes.

If another tuner overwrites my C-C Software can I get it put back for free?

If you have purchased a Flashwire you are able to perform this yourself, however if you have installed your Software through a Custom-Code dealer we would not be able to reflash your Custom-Code software back onto your ECU for free.

How do I install my new Custom-Code Software using FlashWire?

The FlashWire Application that ships with the cable has a PDF instruction manual within it, however you can also download the instruction manual from the Downloads section of this website or directly from here.

How will I know if my FlashWire installed the new Custom-Code Software correctly?

The effects of the new Custom-Code software should be immediately obvious to you as soon as you put your foot down.

Can I use someone else's FlashWire on my vehicle?

Each FlashWire will lock to the first vehicle it's used on. You will not be able to use your FlashWire on any other vehicle after first use.

What if I am not happy with the result?

We’re so confident that you’ll love our software that we offer a 30 day satisfaction guarantee. That means if you’re not satisfied for whatever reason we’ll happily refund you in full within the first 30 days of purchase.

/// What makes Custom-Code Software the best?

Fuel pump

Improved Fuel Economy

With a Custom-Code remap your engine is running more efficiently and therefore you will experience improved fuel economy. With the extra torque you’re also able to change gears lower down the rev range which will return better MPG.

Read More »

30 Day satisfaction guarantee

30 Day satisfaction guarantee

Here at Custom-Code we’re so confident that you will love our remaps that we offer a 30 day satisfaction guarantee. That means if you’re not satisfied for what ever reason then we will happily refund you in full within the first 30 days of purchase.

Read More »

Audi tuner gold

Award winning technology

It’s not just us that think our ECU software is the industry’s best, Custom-Code has won the prestigious Audi Driver Gold Award for tuning the last 6 years running. 

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Engine Reliability

We perform extensive on-road tests with all our maps to ensure your engine not only reaches its full potential but also that it doesn’t cause any unnecessary wear or damage.

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