Mileage Blocker FAQs

Question 1

What is a mileage blocker and how does it work?

Accepted Answer

A mileage blocker — also called an odometer stopper, kilometre freezer, or CAN-bus filter — is a precision electronic module that connects into your vehicle's wiring harness between the speed-sensor network and the instrument cluster. Once active, it intercepts the speed and distance pulses travelling across the CAN (Controller Area Network) bus and replaces them with modified data packets that pause odometer increments in real time. The engine, ABS, traction control, and all other vehicle systems continue to receive valid signals throughout — only the mileage counter is paused. When the device is deactivated or removed, the vehicle returns to its exact previous state.

Question 2

What is a CAN bus and why does it matter for mileage blocking?

Accepted Answer

CAN bus (Controller Area Network) is the communication backbone of every modern vehicle. It is a two-wire network that allows the engine control unit (ECU), ABS module, instrument cluster, gearbox controller, and dozens of other modules to exchange data at high speed. Mileage data — distance pulses from the wheel-speed sensors — travels across this network to be recorded by the cluster and stored in multiple control units. A Carcode mileage blocker sits on this network and filters those specific distance pulses before they reach the recording modules, without disrupting any other data traffic. This is why our units do not cause fault codes or warning lights: the network continues to function normally in every other respect.

Question 3

Are Carcode mileage blockers completely untraceable?

Accepted Answer

Yes. Our units intercept and modify the CAN-bus distance signal before it reaches the cluster and ECU. No mileage data is written to any control unit during operation, and no diagnostic trouble codes (DTCs) are triggered. When the device is removed, there is no record in any module — cluster, ECU, ABS, or gearbox — that the device was ever connected. This is fundamentally different from odometer correction tools, which physically rewrite stored mileage values and can leave forensic traces detectable by professional diagnostic equipment.

Question 4

Does a mileage blocker affect the speedometer or other instruments?

Accepted Answer

No. The speedometer, tachometer, fuel gauge, temperature gauge, and all other instrument cluster displays continue to function normally while the mileage blocker is active. The device filters only the distance-accumulation signal — the specific data that increments the odometer counter. Speed data continues to pass through unmodified, so the speedometer reads accurately at all times. On some vehicles, range-to-empty and average fuel consumption figures may show slightly altered readings while the device is active, as these calculations are partly distance-dependent.

Question 5

What is the difference between a mileage blocker and an odometer correction tool?

Accepted Answer

These are fundamentally different products with different purposes and different legal implications. A mileage blocker pauses the odometer in real time while the device is active — it does not alter any stored value. When removed, the odometer reads exactly what it read before you started. An odometer correction tool (also called a mileage programmer or rollback device) physically rewrites the stored mileage value in the cluster and ECU memory. Correction tools leave forensic traces and are used to misrepresent a vehicle's history — which is fraud. Carcode sells only mileage blockers for legitimate testing and development use. We do not sell, endorse, or support odometer correction tools.

Question 6

How many operating modes does a Carcode mileage blocker have?

Accepted Answer

The number of modes varies by vehicle make and model, but most Carcode units offer between three and six modes. Mode 1 is typically a full pause — zero mileage recorded. Subsequent modes record a fraction of actual distance (for example, one-quarter or one-half of real mileage), which can be useful for calibration or partial-recording scenarios. The exact modes for your vehicle are listed on each product page. Modes are switched using a simple steering-wheel button sequence or high-beam flash — no tools, no apps, no dealer equipment required.

Question 7

Will a mileage blocker cause any warning lights or fault codes?

Accepted Answer

No. Carcode units are engineered to transmit plausible substitute data at the correct voltage, timing, and protocol for your specific vehicle. The ECU, ABS module, and cluster all receive valid signals throughout, so no fault codes are generated and no warning lights are triggered. Cheaper, poorly engineered devices that simply cut the speed signal entirely will cause fault codes because the absence of a signal is itself an error condition. Our units never cut the signal — they replace it with correctly formatted data.

Question 8

Is it legal to buy and install a mileage blocker in the UK?

Accepted Answer

It is entirely legal to purchase, own, and install a mileage blocker in the UK. There is no legislation that prohibits ownership of this type of device. Our products are sold strictly for off-road, track, dyno, tuning, and research and development use — applications where keeping test mileage off a vehicle's permanent odometer record is a legitimate and common requirement. What is illegal — under the Fraud Act 2006 and the Consumer Protection from Unfair Trading Regulations 2008 — is using any device to misrepresent a vehicle's mileage when selling it. Carcode products must not be used for that purpose.

Question 9

Is it legal to use a mileage blocker in Europe and the USA?

Accepted Answer

In most European Union countries and in the United States, purchasing and owning a mileage blocker is legal. The legal boundary in all jurisdictions is the same: using the device to deceive a buyer about a vehicle's true mileage is fraud. In the USA, federal law (49 U.S.C. § 32703) prohibits odometer tampering with intent to defraud. In the EU, Directive 2014/45/EU on periodic roadworthiness testing includes provisions against odometer manipulation. None of these laws prohibit ownership or use for legitimate testing purposes. We recommend customers in all countries review their local regulations and use our products only for lawful purposes.

Question 10

What are the legitimate uses for a mileage blocker?

Accepted Answer

Carcode mileage blockers are used by a wide range of professional and enthusiast customers for entirely legitimate purposes. Common applications include: rolling-road (dyno) testing, where a car may accumulate significant mileage during power runs and calibration; track-day preparation and testing, where repeated high-speed laps would otherwise add unwanted miles to a road car; ECU remapping and performance tuning sessions; pre-delivery inspection and quality-control drives by dealerships and importers; extended diagnostic drives by independent workshops; and development testing by automotive engineers and manufacturers. In all these cases, the purpose is to keep test mileage separate from the vehicle's permanent record — not to deceive anyone.

Question 11

Do I need to declare that I have used a mileage blocker when selling my car?

Accepted Answer

We strongly recommend full transparency when selling any vehicle. If you have used a mileage blocker during ownership, you should disclose this to any prospective buyer and be clear about the circumstances (for example, dyno testing or track use). Failing to disclose information that a reasonable buyer would consider material — including the use of any device that affected the odometer reading — could constitute misrepresentation or fraud under UK consumer protection law. Carcode products are sold for legitimate use only, and we encourage all customers to act with integrity when selling their vehicles.

Question 12

How long does installation take?

Accepted Answer

Most installations take between 10 and 20 minutes. Our units are plug-and-play — they connect directly into the existing wiring harness using the vehicle's own OEM connectors, with no soldering, no cutting of wires, no dealer coding, and no specialist tools required. The most time-consuming part is typically accessing the wiring behind the instrument cluster or under the dashboard, which varies by vehicle. Full step-by-step installation instructions are included with every order, and our UK support team is available by phone if you need guidance during fitting.

Question 13

Do I need any special tools or technical knowledge to install a Carcode unit?

Accepted Answer

No specialist tools are required. Most installations need only a trim removal tool (or a flat-blade screwdriver wrapped in cloth to avoid scratching) to access the wiring behind the cluster or dashboard. Basic mechanical confidence — the kind needed to change a car battery or replace a cabin filter — is sufficient. You do not need diagnostic equipment, a laptop, or any coding software. If you are not comfortable working around your vehicle's interior trim, we recommend asking a trusted independent garage to fit the unit — the installation is straightforward for any competent technician.

Question 14

Where exactly does the mileage blocker connect in the vehicle?

Accepted Answer

The Carcode unit connects into the OBD wiring harness between the speed-sensor network and the instrument cluster — typically behind the dashboard or instrument binnacle. The exact connection point varies by make and model. On most vehicles, the unit plugs in-line using the vehicle's own OEM connectors: you unplug the existing harness connector, plug the Carcode unit in, and then plug the original connector into the other end of the Carcode unit. No wires are cut or modified. The device sits discreetly behind the dashboard and is completely invisible from outside the vehicle.

Question 15

How do I activate and switch modes once the unit is installed?

Accepted Answer

Activation is done entirely from the driver's seat using a simple button sequence on the steering wheel or a high-beam flash sequence — the exact method depends on your vehicle and is detailed on the product page and in the included instructions. There are no apps to download, no Bluetooth pairing, and no external controls. A typical activation sequence might be pressing the OK or Return button on the steering wheel three times in quick succession, or flashing the high beams four times. Each press of the sequence cycles through the available modes. The device retains its last-used mode between ignition cycles.

Question 16

Can the mileage blocker be removed without leaving any trace?

Accepted Answer

Yes. Because the Carcode unit uses the vehicle's own OEM connectors and does not cut, splice, or modify any wiring, it can be removed in minutes by reversing the installation process. Once removed, the original harness connector is simply plugged back in, and the vehicle returns to its factory state. There is no physical evidence that the unit was ever fitted, and — as described above — no electronic record in any control unit.

Question 17

Will fitting a mileage blocker void my vehicle warranty?

Accepted Answer

Fitting any aftermarket electronic device carries a theoretical risk of affecting your manufacturer warranty, and we cannot make a blanket guarantee on this point. In practice, because the Carcode unit is entirely plug-and-play, leaves no electronic trace, and can be removed without any evidence of fitment, it is very unlikely to affect a warranty claim unless the device itself caused a fault — which our engineering is specifically designed to prevent. If you are concerned, we recommend removing the unit before any scheduled dealer service or warranty inspection. We are not responsible for any warranty implications arising from the use of our products.

Question 18

What vehicles are supported?

Accepted Answer

Carcode currently supports over 45 makes and 377 individual vehicle configurations, including Audi, BMW, Mercedes-Benz, Porsche, Volkswagen, Skoda, SEAT, Land Rover, Jaguar, Ford, McLaren, Ferrari, Lamborghini, Alfa Romeo, Maserati, Toyota, Lexus, Honda, Acura, Hyundai, Kia, Mazda, Subaru, Volvo, Polestar, and many more. Each unit is firmware-matched to your exact make, model, year range, and instrument cluster type — not a generic solution. Use the vehicle finder on our shop page to check compatibility for your specific car.

Question 19

How do I know which unit is correct for my vehicle?

Accepted Answer

Each product listing specifies the exact make, model, year range, and cluster type it supports. If you are unsure, the safest approach is to send us your vehicle's VIN (Vehicle Identification Number) along with a photo of your instrument cluster and your exact model year. Our team will confirm the correct unit before you order. You can do this via the contact form on any product page or by emailing info@mileageblocker.com. We would rather spend five minutes confirming compatibility than have you order the wrong unit.

Question 20

My vehicle has a digital or virtual cockpit — does that affect compatibility?

Accepted Answer

Digital instrument clusters (such as Audi Virtual Cockpit, BMW Live Cockpit, Mercedes-Benz MBUX digital dash, or Volkswagen Digital Cockpit) use the same underlying CAN-bus architecture as traditional analogue clusters. Carcode units are specifically engineered and tested for digital cluster variants where applicable — the product listing will specify whether a digital cluster version is supported. If your vehicle has both a standard and a digital cluster option, make sure you select the correct variant when ordering.

Question 21

Do you support BMW vehicles specifically?

Accepted Answer

Yes. BMW is one of our most extensively supported makes. Due to the complexity of BMW's CAN-bus architecture — which varies significantly across chassis generations, engine variants, and cluster types — our BMW products use a two-step selection process on the product page: first select your chassis generation (for example, F30, G20, or E90 for the 3 Series), then select the specific device version for your cluster type. This ensures you receive a unit that is precisely matched to your vehicle's electronics. We support a wide range of BMW models including the 1, 2, 3, 4, 5, 6, 7, 8 Series, X3, X4, X5, X6, X7, M2, M3, M4, M5, and more.

Question 22

My car is not listed on your website — can you make a unit for it?

Accepted Answer

We are continuously expanding our range. If your vehicle is not currently listed, please contact us with your make, model, year, and VIN. We maintain a development pipeline and prioritise new vehicles based on customer demand. We cannot guarantee a timeline for new vehicle support, but we do keep a waiting list and will contact you when a compatible unit becomes available. Alternatively, if you have a vehicle that is closely related to one we already support (for example, a badge-engineered variant or a model that shares a platform), it is worth enquiring — compatibility is sometimes broader than the listed models suggest.

Question 23

What payment methods do you accept?

Accepted Answer

We accept all major credit and debit cards (Visa, Mastercard, American Express), Apple Pay, and Google Pay. All payments are processed securely through Stripe, which is PCI DSS Level 1 compliant — the highest level of payment security certification. We do not store your card details on our servers. Prices are displayed in GBP and include UK VAT where applicable.

Question 24

Do you offer discount codes or promotions?

Accepted Answer

We run occasional promotions and discount codes, which are announced via our newsletter and social media channels. You can enter a promotion code at checkout. We do not offer permanent discount codes or bulk-purchase pricing through the website, but if you are purchasing multiple units for a fleet, workshop, or commercial application, please contact us directly to discuss pricing.

Question 25

Can I place an order by phone?

Accepted Answer

Our online checkout is the most efficient way to order, as it allows you to select the exact vehicle configuration and options for your unit. However, if you prefer to place an order by phone or have questions before purchasing, our team is available on 0330 043 6312 during UK business hours. We can also take orders via email at info@mileageblocker.com.

Question 26

Do prices include VAT?

Accepted Answer

All prices displayed on MileageBlocker.com include UK VAT at the current standard rate of 20% for UK customers. If you are ordering from outside the UK, VAT will not be charged at checkout — prices shown are ex-VAT for international orders. Import duties, taxes, and brokerage fees for international deliveries are the buyer's responsibility and are not included in our prices.

Question 27

Do you ship worldwide?

Accepted Answer

Yes. We ship to the UK, Europe, USA, Canada, Australia, and most countries worldwide. All orders are dispatched from our UK facility using DHL Express, FedEx, or Royal Mail depending on your destination. Shipping costs and estimated delivery timeframes are displayed at checkout based on your delivery country. All orders include full tracking.

Question 28

How much does shipping cost?

Accepted Answer

UK orders: Royal Mail Tracked 48 is free; DHL Express next-day is £12.90. France and Ireland: DHL Express £34.90. Most of Europe (EU + EEA): DHL Express £39.90. Canada: DHL Express (DAP) £44.90. Asia-Pacific and Middle East: DHL Express £59.90. United States: FedEx (DDP, duties paid) £59.90. Rest of World: DHL Worldwide Express £69.90. All rates are shown at checkout before you pay.

Question 29

How long will my order take to arrive?

Accepted Answer

UK free delivery (Royal Mail Tracked 48) typically arrives in 2–3 working days. UK DHL Express arrives next working day. European orders via DHL Express typically arrive in 2–4 working days. USA orders via FedEx arrive in 3–5 business days. Asia-Pacific and Middle East orders via DHL Express typically arrive in 3–6 working days. Rest of World orders via DHL Worldwide Express typically arrive in 4–7 working days. All timeframes are indicative and subject to customs clearance for international orders.

Question 30

Will I have to pay import duties or customs charges?

Accepted Answer

For orders delivered outside the UK, import duties, taxes, and brokerage fees are the buyer's responsibility. These charges vary by country and are determined by your local customs authority — we have no control over them and cannot predict the exact amount. We provide all required commercial documentation to the freight carrier to minimise the risk of customs delays. If you refuse delivery or fail to pay import charges, causing the goods to be returned to us, the cost of return shipping and any associated fees will be deducted from any refund due.

Question 31

Can I track my order?

Accepted Answer

Yes. All orders include tracking. You will receive a dispatch confirmation email with your tracking number once your order has been collected by the carrier. UK Royal Mail orders can be tracked at royalmail.com. DHL and FedEx orders can be tracked on the respective carrier websites. If you have not received a dispatch email within two working days of placing your order, please check your spam folder and then contact us.

Question 32

Do you offer same-day or next-day dispatch?

Accepted Answer

We aim to dispatch all orders placed before 1pm on working days on the same day. Orders placed after 1pm or on weekends and bank holidays are dispatched on the next working day. DHL Express collections are once daily — we cannot guarantee same-day collection for orders placed close to the cut-off time. If your order is time-sensitive, please contact us before ordering and we will do our best to accommodate your requirements.

Question 33

What is your returns policy?

Accepted Answer

We offer a 30-day money-back guarantee on all orders. If you are not satisfied for any reason within 30 days of receiving your order, contact our UK support team and we will arrange a return and refund. Goods must be returned unused and in their original, undamaged condition and packaging. A 3% cancellation fee applies to non-faulty returns to cover payment processing and administrative costs. Original outbound shipping costs are non-refundable. Refunds are issued within 14 calendar days of receiving the returned goods.

Question 34

What warranty do Carcode products carry?

Accepted Answer

All Carcode products carry a 12-month warranty against manufacturing defects from the date of purchase. If your unit develops a fault within the warranty period, contact us at support@mileageblocker.com with your order number, a description of the fault, and supporting evidence (photographs or a short video). Upon verification, we will offer a repair, replacement, or full refund at our discretion. The warranty does not cover damage caused by misuse, incorrect installation, or physical damage. Your statutory rights under the Consumer Rights Act 2015 are not affected.

Question 35

My unit is not working correctly — what should I do?

Accepted Answer

First, check that the unit is correctly seated in the harness connector — a partial connection is the most common cause of issues. Then verify that you are using the correct activation sequence for your vehicle (refer to the instructions included with your order or the product page on our website). If the unit appears to be active but the odometer is still incrementing, check that you are in Mode 1 (full pause) rather than a partial-recording mode. If you have checked all of the above and the unit is still not functioning correctly, contact our support team on 0330 043 6312 or at support@mileageblocker.com with your order number and a description of the issue.

Question 36

How do I contact Carcode support?

Accepted Answer

Our UK-based support team is available by phone on 0330 043 6312, by email at support@mileageblocker.com, and via the contact form on our website. For pre-sales compatibility questions, email info@mileageblocker.com. We aim to respond to all enquiries within one working day. Our office address is Unit A, 82 James Carter Road, Mildenhall, IP28 7DE, United Kingdom.

Question 37

Can I return a unit if it is not compatible with my vehicle?

Accepted Answer

Yes. If a unit is not compatible with your vehicle despite being listed as compatible, we will arrange a full refund or exchange at no cost to you. To avoid compatibility issues, we strongly recommend sending us your VIN and cluster details before ordering if you have any doubt. If you ordered the wrong unit due to an error in your vehicle selection, our standard 30-day returns policy applies — the unit must be returned unused and in original packaging.

Technology & How It Works

Legality & Intended Use

Installation & Setup

Vehicle Compatibility

Ordering & Payment

Shipping & Delivery

Returns, Warranty & Support

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