Originally Posted by audifirst

check all the fuses at fuse panel, but I have feeling when your car was jump started it was connected wrong orginally,..which could damaged one or couple of your car components , I have seen that a lot lately, doing a lot of repairs, it is painstaking process now you need to disconnect each component and check if the connection can be made, usually either of the components are damaged they still will function but the diagnostics connection is damaged could be instrument cluster,radio,ECU, ABS, tranny ECU,

Originally Posted by Jenspadafora

Hi, I'm hoping someone sees this and can help. I have an Audi TT that has a check engine light on and it won't connect. All of the fuses were checked and I was at a loss of what to do until I read your post. When the battery was recently jumped, it was connected wrong so this must have damaged a component. Can you walk me through how to find out which component and what to do about it?