HERE IS HOW IT IS DONE FOR REAL.
REASON: Because at least in Onstar equipped cars, the spy system and cell uplink is such a huge system it has its own fuse that you can just pull out. And you had better pull that fuse Because if we have a civil war, they will probably fake an EMP and use the Onstar system to shut your Chevy down. And they will use it to spy, know you are part of the rebellion, and crash you at full throttle. That is going to happen and people had better be ready for it.
IMPORTANT: There are either idiots or bold faced scammers saying all OBD2 and newer cars can be wiped out easily with EMP. HERE IS THE TRUTH: Many test runs have been done with this to see what it takes to shut down a car with electronic interference. And during the test trials, it took an average of 80, 000 watts of RF energy beamed directly at a car to shut it down. An in all cases, after a stall was triggered, the cars worked normal afterwards. This is because CARS ARE G*D* FARADAY CAGES THAT BLOCK EMP. (That alone ought to let you spot an EMP hoaxer with regard to this convenient excuse to use when they use the CELL PHONE NETWORK TO SHUT ALL (OR SELECTED) CARS DOWN.) So the forced electronic shut down via police car mounted jamming was given up on, it was so hard to accomplish it was considered not worth it.
A nuclear EMP would never hit your car with more than a few hundred watts in a worst case scenario because the energy is very dispersed. Forget the hoaxters that are pushing the lie that "EMP will kill your car" because it is patent BULLSHIT.
Due to the frequencies they use, cell phones work in cars because the signal will go through the glass. BUT ALL NUCLEAR EMP IS AT AM FREQUENCIES, and I challenge you to take even a G.E. super radio, put it in the center of a car away from the windows and try to get a station to come in. AM only works on car radios because of the external antenna.
How much harder would it be then for any EMP to make it to your car's electronics which are in areas that have no windows, especially since a nuclear EMP would come from above the car? There are many other technical reasons why nuclear EMP won't take a car out, but that is one I can say that anyone would understand. The nuclear EMP ruse only works in liberal crap films like "the day after" where truth takes more than a back seat, it rides the bumper.
MEXICAN ANONYMOUS