Originally Posted by elp_jc
Wishful thinking. If dealer suspects a mod caused the failure they simply deny coverage. Plus they 'flag' your car, so every dealership will be aware of it. So the burden of proof is on YOU, not to mention you'd need to hire a lawyer to bring a lawsuit. The more reasonable approach is arbitration, like it was mentioned above, but if you messed with the ECU (any tune, including disabling O2 sensors), you're probably going to lose either way. And in you deleted the cats (a federal offense), your odds are even more bleak.
I personally can't understand why people risk damaging their cars and/or losing their warranties with anything other than catbacks and/or wheels when car is covered, but to each his own. No smart person (juror or judge) is going to deny that tampering with the ECU could have changed something that fried the engine, so that M&M is not going to do crap for you since most owners reverse anything done anyway before a dealer's visit. All BMW has to do is provide evidence of tampering and you're toast. And yes, at least the factory can easily do that. Good luck man.
According to the Magnuson Moss Act, The Burden of Proof is on the Dealer.
The Act places a number of conditions on the language of the warranty itself, in that it must be clear and unambiguous. What's more, it must specify in very simple terms the conditions under which the warranty may not be valid. Can an automotive dealership void your warranty?
Understanding the Magnuson-Moss Warranty Act of 1975.
Nearly everyone has heard about someone who has taken a vehicle that has been modified with aftermarket parts to a dealer for warranty service, only to have the dealer refuse to cover the defective items. The dealer usually states that because of the aftermarket parts the warranty is void, without even attempting to determine whether the aftermarket part caused the problem.
This is illegal.
Vehicle manufacturers are not allowed to void the vehicle warranty just because aftermarket parts are on the vehicle. To better understand this problem it is best to know the differences between the two types of new car warranties and the two types of emission warranties. When a vehicle is purchased new and the owner is protected against the faults that may occur by an expressed warranty - an offer by the manufacturer to assume the responsibility for problems with predetermined parts during a stated period of time. Beyond the expressed warranty, the vehicle manufacturer is often held responsible for further implied warranties. These state that a manufactured product should meet certain standards. However, in both cases, the mere presence of aftermarket parts doesn't void the warranty.
There are also two emission warranties (defect and performance) required under the clean air act. The defect warranty requires the manufacturer to produce a vehicle which, at the time of sale, is free of defects that would cause it to not meet the required emission levels for it's useful life as defined in the law. The performance warranty implies a vehicle must maintain certain levels of emission performance over it's useful life. If the vehicle fails to meet the performance warranty requirements, the manufacturer must make repairs at no cost to the owner, even if an aftermarket part is directly responsible for a warranty claim, the vehicle manufacturer cannot void the performance warranty. This protection is the result of a parts self - certification program developed by the Environmental Protection Agency (EPA) and the Specialty Equipment Market Association (SEMA).
In cases where such a failed aftermarket part is responsible for a warranty claim, the vehicle manufacturer must arrange a settlement with the consumer, but by law the new - vehicle warranty is not voided.