Dear Members

I am new to audi, just got a B6 A4 1.8T CVT 2002 (multitronic) and it has a problem with the transmission.

when I start the car, for two minutes the transmission is OK and after that it goes into the limp mode (Flashing PRND)
one more thing is, it only goes into normal mode when I cold start it! (when it is warm, it is in the limp mode from the start)

Car has 98K miles and the transmission oil chaged at 70K according to its service history

what do you think,
any recall on the transmission?
software upgrade for the TCM ?
changing transmission oil again?
replacing TCM? any other Idea
Does anyone had a similar problem?

Thanks