Ok so I picked up a little 05 gti auto and about 3 days after having it the check engine light came on. Nothing changed with the vehicle when the light came on but I went and got it scanned with the basic scanner at auto zone. It gave a code related to 4th gear. Then the next day it started not shifting into 4th gear. When it would try the engine would do the thing where it revs high until it goes back into a lower gear. I've been real busy the last couple weeks and work is real close so Ive just been driving it in 1st-3rd. Well today I finally decided to try unplugging the battery to see if it would change anything. And to my very happy surprise the engine light went off, and I took it on a drive and the trans shifted normally. Is anyone familiar with this issue and what it might take to fix it? Im guessing the light is going to come back on and 4th will start acting up again soon. I bet it was doing it before I got it and the guy just reset it right before selling it.