I have a '00 323i e46, auto transmission. Recently the transmission light came on while driving and the car went into "limp mode". The auto trans was shifting rough. I pulled over, shut the car down for a a minute and started it back up. The light was still there. I was only a mile from home so I limped my way back. I left the car off for 20 minutes and the transmission light did not come back on after starting it up. It's been about a month since this happened and the light has yet to appear. Any ideas of what would cause this one time fault?