I've searched the boards and found that some of you have ended up with different problems when your TCS and check engine lights came on. My question is in most cases does this seem to be the carbon build up problem or is it usually the tranny. I have about 71,000 miles on my 99 TL. It's certified so I still have the 100,000 mi warrantee on it. Will the dealer cover either issue at no cost to me? Will I have to pay some of the cost? How does this work? I've never really had to use my warrantee before now.