Should Modifying Your Car Be Illegal?

working on own car

Driveway tinkerers and shop-bound weekend racers could be a dying breed.

There are two main reasons for this:

  1. People who work on their own cars are stymied by the sheer amount of technology and custom tools needed to do the job.
  2. A new law could make it illegal to work on your own car.

The first reason is a natural consequence of technology. Open the hood of a modern car, and instead of seeing headers and valve covers, we’re greeted with a plastic cover emblematized with the vehicle’s logo and engine size.

Aside from having easy access to refill the windshield-wiper fluid, modern cars are basically untouchable for the average weekend do-it-yourselfer.

That in itself isn’t so bad, but a law that would outlaw us from even trying is very scary. And very real.

Car blogs and enthusiasts all over the country are exploding with comments on the efforts by the Auto Alliance, made up of a group of 12 major automakers, to use the Digital Millennium Copyright Act to make it a violation of copyright law to work on, modify, or tinker under the hood of a personal vehicle.

In short, that would mean vehicle owners would be breaking the law by removing that plastic cover and attempting to repair or modify parts underneath.

This is a complicated and convoluted matter, which Jalopnik did a nice job of covering in a lot of detail. Feel free to read through it if you have the time. I’ll quote the Auto Alliance’s statement from that article, which summarizes their position (it’s long, but necessary):

Automobiles are inherently mobile, and increasingly they contain equipment that would commonly be considered computing devices… Many of the ECUs embodied in today’s motor vehicles are carefully calibrated to satisfy federal or state regulatory requirements with respect to emissions control, fuel economy, or vehicle safety. Allowing vehicle owners to add and remove programs at whim is highly likely to take vehicles out of compliance with these requirements, rendering the operation or re-sale of the vehicle legally problematic. The decision to employ access controls to hinder unauthorized “tinkering” with these vital computer programs is necessary in order to protect the safety and security of drivers and passengers and to reduce the level of non-compliance with regulatory standards. We urge the Copyright Office to give full consideration to the impacts on critical national energy and environmental goals, as well as motor vehicle safety, in its decision on this proposed exemption. Since the record on this proposal contains no evidence regarding its applicability to or impact on motor vehicles, cars and trucks should be specifically excluded from any exemption that is recommended in this area.

So basically if a car owner wanted to change his or her own oil or replace brake pads, there’s no problem. But if he or she wanted to reflash the ECU to get more horsepower, that would be a copyright violation. Even plugging into the OBD port to check for engine codes could potentially infringe on the automaker’s rights.

Things get a little muddy if someone wants to change a part that affects how the ECU receives its information, such as installing larger tires. If the ECU is programmed for stock tires, bigger ones will change how information is processed and could, potentially, create a violation.

This is all still new, and the idea isn’t hashed out enough to become a law, but it’s something that 12 of the world’s largest automakers seriously want to see happen.

I’m of the belief, like the writer of the Jalopnik article, that if I purchased something, I have the right to modify it as I see fit.

If you feel the same way, the Electronic Frontier Foundation has stepped up to protect vehicle owners and has started a petition you can sign if you’re so inclined to voice your opposition.

Should modifying your car be illegal?


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  1. I am a automotive tech for Goodyear, and messing with the computer controlled systems is bad news. They usually try to get better acceleration, but ends up messing up not only the fuel ecomomy, but can burn up the catalytic coverter, cause knocking which another system tries to correct by altering the fuel injection, air.fuel mix, and engine timing which causes poor performance in ways that might be covered up but can cut the usable life of the car by 50,000 miles. I have driven some of these and they invaribly fail emission tests by huge amounts, the power steering, tuned to neutral out oversteer or understeer, instead CAUSES it. A guy tried to blame our tires for having bulging sidewalls, but his mods had made so much oversteer that for months he was hitting the curb when he only meant to change lanes. Likewise ABS correction for traction may make things worse with unexpected acceleration patterns. A guy took off the rpm limit on an Audi A4 with 65K miles on it camshaft snapped $7500 for a new engine. This method using DCMA is sneaky but these mods do little good and can do thousands in damages as well as make the car less safe,. You may own the car, but you never own software, you LICENSE it, so te people yelling most are aftermaket hardware vendors and the gurus who make unrealistic promises if you send them your chip and $1,000 money transfer

  2. To address the initial question posed by the title, “Should modifying you car be illegal?”; In a sense it already is. Under current motor vehicle laws governing motor vehicle emissions, any tampering with emissions controls, including this type of ECU “flashing” that changes fuel mapping and such in the engine and/or transmission control modules, is not allowable. Such modifications have been happening since emissions controls were installed on vehicles in the late 60’s and early 70’s. Back then, the tolerances for emissions non-compliance were much larger than today’s computer controlled cars. There are untold number of cars out there right now violating these laws, both knowingly and unknowingly right now. Just removing a SMOG pump form your 1977 Monte Carlo or putting a cat-less exhaust on a 93 Civic could land you jail time if the powers that be wanted to crack down on this issue. This seems to be more manufacturers trying to cover their proverbial backsides that blatantly forbidding consumers from customizing their rides just because they want to put their foot down on the little guy. I believe what these 12 manufacturers are trying to accomplish is to clarify the existing laws, or supplement them, to account for new and future technologies in order to remove liability from themselves if a consumer were to render the emission compliance mute after modification.
    That being said, I DO NOT support an outright ban on DIY auto mechanics. As a professional mechanic, I have had to fix many a botch job done by incompetent DIYers, many of which caused more issues than it helped or made the car unsafe, but no law should prohibit someone working on his/her own vehicle. I DO, however, support the idea of licensing for professional mechanics. Such a license would not apply to the casual home mechanic unless a fee is collected for services rendered.
    SUMARY: The proposition discussed in this article is not malicious, but rather a “cover-our-asses” tactic with the possible consequence of restricted DIY freedom, although it is too early to tell and the implications will not be clear until more details are hashed out and actual law is proposed.

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