Like all sentencing guidelines incorporated into penal codes, the "life" part here is meant as an upper limit, not an automatic sentence. In fact, I suspect the actual language of the law merely states the level of the crime (Class A Felony or something along those lines) and that places it in the realm for such a sentence. So, some kid just piddling around and getting into the car's system could only get some light sentence (a couple months or probation) while also allowing more hefty sentences to someone who might try some dangerous pranks like disabling power on a car on the highway.
The intent is that there is a more deterrent force to the law for the more egregious actors out there. As it stands, without this law, someone who hacks a bunch of different cars, does whatever it is they want to the systems by disabling engines, screwing around with systems, disabling locks, etc., the only choice of prosecutors would be to piece together legal theories to make a more substantial case. The goal by making this law here is to simplify that by making it a specific law to point to.
It is the same rationale to why there were laws created about breaking into a car specific and separate from breaking into houses, even though prior to those laws the two were merely considered personal property and legal issues were settled on those terms. It is, I would argue, where the legal process has fallen behind in the internet age - theft of personal information and content over the internet has a weak legal framework, left for it to be defended under legal theories that are traditionally used based on physical property.