Going outside on a warm Saturday afternoon and working on your car is as American as apple pie, for now at least.

The Auto Alliance, a special interest group representing 12 big automobile companies from Ford to Toyota, is pushing an interpretation of a law called the Digital Millennium Copyright Act (DMCA) that would put this do-it-yourself tradition in danger.

These 12 car companies are lobbying hard to make working on the electrical and computer components of your own car illegal. General Motors has told the Copyright Office that proponents of copyright reform mistakenly “conflate ownership of a vehicle with ownership of the underlying computer software in a vehicle.”

General Motors also says that your car qualifies as a “mobile computing device.” Tinkering with it, therefore, could be a copyright violation because although you do own your car, you do not own the computer code inside it. Jail-breaking your iPad is currently illegal for the same reason. By the way, jail-breaking your iPhone is still legal; it’s just one more example of a government regulation that is full of double standards.

The Auto Alliance argues that modern cars are so complex that working on advanced components could be dangerous. It warns that someone could also maliciously hack the code in your car’s software. It’s unclear exactly what kind of modifications would meet the new standard.

John Deere goes even further, making the case that you don’t actually own the tractor you buy. You’re just given a license to use it for an extended period of time. John Deere believes owners of tractors have “an implied license for the life of the vehicle to operate the vehicle.” It also warns:

Letting people modify car computer systems will result in them pirating music through the on-board entertainment system.

But should they be so concerned about the potential for pirating music that they don’t even let tractor owners modify their own tractors?

Tesla, which makes arguably the most advanced cars in the world, does not support limiting owners’ rights to work on their cars.

Critics say the automakers just want a larger share of the automobile repair and aftermarket industry.

The Electronic Freedom Foundation is fighting this new interpretation of the law, calling the DMCA, which was passed in 1998 with the intention of reducing online piracy, an innovation killer. It claims that the Auto Alliance wants to treat everyone who modifies his or her own car as though he or she were a pirate.

If car companies want to void your warranty for working on your car, that’s their right. If they want to lease out cars instead of selling them, that’s fine too, as long as they are clear that they’re only leasing you the car.

But claiming that you don’t really own all or part of your car is an affront to the very idea of property rights. If you buy a car, you should have the right to do whatever you want with it. It’s your car, isn’t it?