Is Car Coding Legal? Covering all the legal spectrum


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If you are interested in coding your car one of the questions that you might be asking is if car coding is legal?

Car coding is usually used for unlocking hidden features in your car and giving it a personal touch! Typically, to do this, you can go to a mechanics workshop and have your car coded by technicians. However, the coding service is usually expensive and depending on features that you’d like to code you could be charged several thousand dollars.


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Nevertheless, if you own a suitable OBD2 scanner you can code your car by yourself and save a lot of money. Your only cost will be the one time payment for the OBD scanner and mobile app. However, once you have your own OBD equipment, you can code your car as often as you want!

Having this type of access to your car’s ECUs can make you wonder if this is legal. In short, car coding is generally legal and permitted. However, there are some points regarding legal concerns that you should consider and today we will dive deep into these!

legal car coding

Is car coding legal?

Whether or not car coding is legal, it depends on the type of modification made to the car. Making changes to a vehicle can violate criminal law, administrative law, and contract law. Those who violate legal regulations should expect consequences. These range from a warning to imprisonment.

Breaching a contract agreement is an example of violating a legal regulation. For example, many states in the USA demand mandatory car insurance in order to be allowed to drive your car on the road. There are cases where some insurance contracts specify that car coding can be a violation of the contract. Therefore, the insurance company may deny benefits to you if you code your car. 

Moreover, legal concerns also exist about the software used. For example, many OBD readers and apps that are available online (Such as Carly) are legally unobjectionable. In other words, these tools are legal to be manufactured and sold.

However, if anyone purchases original OBD software solutions from unauthorized distributors, they may be liable to prosecution. Therefore, the easiest way to avoid this is to purchase the OBD equipment from the original manufacturer.

If you ask a lawyer if car coding is illegal, you will probably get the following answer: It depends. Lets dive deeper to see where the legal pitfalls lie! 

Legal car coding: what you need to know

There are two main things that you need in order to code a car. Firstly, you will need the hardware to access your car’s information (i.e. an OBD scanner). Secondly. you will need a software (or an app) to control your car’s data and customize features.

The car coding possibilities that you’ll have depend on the software (or app) that you use. There are many commercial OBD solutions, such as Carly, that give you a wide array of coding options.

However, if you use the original software from the car manufacturer, you will have even wider coding possibilities. Unfortunately, the original software of car manufacturers is not available on the market due to intellectual property…at least not legally.

Even though this software is not available for consumers, it is still offered for purchase… which is illegal! This is because the original software has most likely been copied illegally and also distributed illegally on the Internet.

If you purchase pirated software (which in essence is stolen property), you can be found guilty of a criminal offense. Therefore, the first recommendation that we can give you is to be informed about the origin of the software that you’ll purchase.

If you are interested in purchasing an OBD scanner that comes with its own software, you should be safe. This is because commercial solutions, such as Carly, develop their own software and hardware from scratch, without using a car’s manufacturers software.

Like having your own mechanic!

Coding and the 3 areas of the law

Now that we have covered the first step, you might still be wondering if the coding itself is legal? Even when you code your car with legal software, you can still violate the following areas of the law:

Criminal law

Administrative law

Civil law (contract law).

As a car driver, you are always operating within the boundaries of criminal, administrative and contract law. For example, a harmless car crash leads to the application of administrative and civil law. If people are injured in the car crash then criminal law comes into play, even if it is only a small bruise. 

If you want to code your car, these areas of law regulate what is allowed. Anyone who oversteps the boundaries of legality will face the consequences. Unfortunately, ignorance is not bliss here, as saying “you didn’t know” won’t help your case.

Since legal texts are usually long, we have done the research for you and found the most important information that you should consider. Let’s start with the first area of law and see how it relates to car coding.

Criminal law – when is car coding a criminal offense?

Fraud in car sales is one of the most common criminal offenses. Many car sellers manipulate the odometer of used cars in order to sell them at a higher price. In fact, about a third of used cars have been manipulated. According to the law, anyone who commits odometer fraud is subject to punishment or even imprisonment.

This type of fraud has existed for many years. Back then, it used to be common to use a drill for reversing the mileage of used cars.

Nowadays, the technology for reversing the mileage in modern cars has changed and it’s done through car coding. With coding, tampering a car’s odometer only takes only a few minutes. However, this kind of tampering can be detected because cars have various control units built in that you can use to verify the mileage.

So, if you want to manipulate a car’s mileage, you will have to manipulate various control units. Otherwise, if one control unit is missed, odometer tampering can be easily detected.

In conclusion, a mileage reset is not a trivial offense. In the United States, odometer tampering is a felony, as described in the Federal Odometer Act, and you can get fined up to $100,000. Therefore, the question whether this kind of car coding is legal is pretty straight forward. In this case, car coding to reverse car mileage is a federal criminal offense and its subject to fines or imprisonment.

Administrative law

Administrative law relates to many matters that accompany a person throughout their life. This includes traffic and road safety. There are many laws that regulate road safety which include the legal requirements that must be met in order to drive on public roads.

It’s not always easy to know when car coding violates an administrative law and when car coding is legal. One common example regards the coding of your vehicle’s headlights and taillights.

Changes to these lights are popular since you can make your car more unique. After all, it is very tempting to customize the lighting to your taste and can be quickly done through car coding

However, it is often overlooked that there are mandatory law regulations for car lights. For example, some countries have regulations about the colour or brightness of parking lights.

In the U.S, it is illegal to have red lights on the front side of your car. Additionally, flashing and non-stationary lights are strictly prohibited. You will face a fine if you code your lights in violation of car lighting regulations. Additionally, the car lights will need to be restored to the proper conditions. 

As you can see, the question of whether or not car coding is legal cannot be answered with a simple yes or no. It all depends on what feature of your vehicle you’re changing. Therefore, we recommend that you check out the road safety laws of your country or state before coding your car.

Contract law – Pacta sunt servanda

Pacta sunt servanda is one of the principles of contract law. In Latin, this translates to “agreements must be kept”. This means that you have to honor contracts that have been made and expect every player to behave in accordance with the contract.

But what does this have to do with your car? After all, you already signed a sales contract, paid the purchase price and got the car. You are right. However, even after signing a contract there are still contractual obligations, such as the warranty, that have to be fulfilled.

Legal car coding: Does it affect your car’s warranty?

legal car coding

By law, car dealerships must always provide a warranty clause in every car sale contract. The seller of the car is liable for certain contractually guaranteed properties. For example, if there is a defect, the seller must take responsibility for it and repair it. Though in the case of private car sellers, they can contractually exclude the warranty.

Let’s assume that you purchased a new car from a car dealership. Can you claim a repair under the warranty clause if you made a mistake while coding your car? Can car dealerships and car manufacturers refuse to honour the warranty clause? Once again, if you ask a lawyer if coding is legal under this scenario they would respond: it depends.

It is possible that your car warranty might not apply if the contract states that car coding was the reason for your car’s malfunction. We recommend you to be aware about what’s stated in your contract’s warranty clause. 

Actually, it is common for car manufacturers to dislike customers to code their cars. This is because car manufacturers charge a price for car coding. Therefore, they try to include clauses in the contract stating the rejection of warranty claims in case of car coding.

Still, if your car presents a malfunction due to car coding, the car dealer must prove that coding is to blame. And if the damage was indeed caused by faulty car coding, then they might reject the warranty claim and you would have to pay for it yourself. However, doing a mistake while coding your car doesn’t mean that coding is illegal. The only “damage” that you would have to bear would be any costs to repair your car.

Is it legal to unlock features of your car?

What happens if you manage to unlock features in your car that are normally only available if you pay an extra fee for them?

Let’s assume that you purchase a car with a rear view camera but this feature is not activated. In this case, since it’s already installed it only needs to be activated through car coding. Car manufactures would be able to perform this for you. However, they usually offer the coding service at a steep price.

If their coding services are too high for you, you can code the feature yourself. All you would need is an OBD2 scanner and a mobile app. This equipment might cost you around $100 or a little more. However, that is usually still more affordable and you can also code as many features as you want, whenever you want! 

The only difference between coding your car at a mechanics workshop versus by yourself is only the cost. However, is car coding still legal?

The fact is that once you have acquired full ownership of your car, you are free to code whatever you want since it’s your property…as long as it abides by any laws. So activating and using an already installed rear camera would be fine.

In our example, there is no violation of criminal law because there is no intent to commit fraud. Additionally, there is also no violation of administrative law. The opposite is true. In fact, activating the rear view camera offers more safety to the vehicle.

The situation would be different if the contract stated that you can only activate such features via the contractual partner. However, in this case, you would probably not sign the sales contract, so these cases are rare.

Legal car coding: Does it affect your car’s insurance? 

By law, many countries require motor vehicle liability insurance. Additionally, if you want higher insurance coverage, you can take out comprehensive insurance. 

But will the insurance company cover the damage if you have coded your car? Taking a look at your insurance contract can save you from breaching the contract.

Before coding your car you should ask the insurance company about the consequences. In principle, car coding is legal. However, the insurance company may refuse to pay for damages if the car has been coded. This would mean, for example, that in an accident, the insurance would not cover the damage and you would have to pay for the costs.

Conclusion: The answer is anything but simple

As you can see, it is not so easy to determine if car coding is legal. Basically, car coding is legal as long as you do not violate any applicable law.

However, you might face unpleasant consequences even when the car coding is legal. An example of this is when the insurance company sees it as a breach of contract and declines benefits if car coding has been performed. Or if your warranty is no longer valid after certain codings.

In order to avoid legal consequences, we recommend you to check if you are in breach of any law or contractual provision before coding your car.

Now that we’ve covered all the legal basics, we hope you feel prepared to try coding! With a commercial app such as Carly, you won’t be guilty of buying stolen property and will be able to code as many features as your want.

The sale, purchase, and use of the Carly OBD scanner and app are legally permitted. So as long as you follow the legal regulations from your home country, sit back, relax and start customizing your car!

Like having your own mechanic!

Keep in mind, that every car has different software and modules built-in. Therefore specific features will vary with every model.

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