No - Mike took the "bad" gas cap off his car, popped the tracker out, and hooked it up to a radio so it would run the AA battery down.
He had put a matching gas cap on the car with HIS OWN tracker inside, so when the bad guy got the low battery indicator on his gauge,
and came to Mike's place and replaced the tracker on the car, he took what he presumed was the gas cap with his tracker with a dead battery in it (and rather than hang by the car and do all that there, and maybe be seen, figure he'd probably take it home and put a new battery in it there).
But since he took the cap with Mike's good tracker in it, now Mike can follow HIS tracker and find where the bad guy went (and figure WHO the bad guy is!).