So I have this 20.00 scan tool that reads and clears codes. The last time I got this code, two weeks ago, I replaced the gas cap and cleared the code, and thought that was it. Last week it came on again. I tightened the gas cap, cleared the code... and it’s on again as of last night. So, it ain’t the gas cap ! Lol. There are SO MANY other things it could possibly be! But before I start replacing each part one by one... Is there a relatively inexpensive scan tool that will pin-point what the exact problem is ? P0455 is such a generic code!