Legal Question in Criminal Law in Tennessee

I suspect what you mean to say is "Can the state of Tennessee forfeit (take away forever) my car if I am arrested for "simple possession of marihuana."

No, not if that is the only charge.

If relevant, the car can be seized as evidence until the trial, and then returned after trial.

If you were originally arrested for a felony charge, the car might be forfeited while you await trial, because the forfeiture proceedings take place usually before trial on the underlying charges.

Worst case: If you were arrested for felony drug charges, and the State files to seize your car, and you either don't fight the forfeiture or fight it and lose, and afterward go to court and are convicted of only a misdemeanor (either because of a plea agreement of a jury verdict to a lesser offense) you don't get your car back.

So fight early and hard to keep your property.