I have a 2006 Audi A4 2.0T FWD with almost 90k. MIL code reads p0706. Now, I know the issue is with the TCM but I have gone to the dealer and they tell me it's a throttle body issue, the time after when I approached the dealership they said it needs a new TCM. A different independent shop is telling me it is an issue with the valve body. Another independent shop is saying I need to possibly replace a switch that switches Park and Neutral. Everywhere I look online in forums, etc. I read that my TCM needs to be replaced or my transmission needs to be replaced. My symptoms are MIL, PRND flashes on dash. After a few hours of not driving, PRND doesn't flash (and MIL goes away if I turn my engine on and off a few times) and stays as it should normally until I try to switch to reverse, in which case nothing flashes or lights up and reverse fails. In which case I put the car in Park and PRND starts flashing again. I've had this issue for almost a year now and nothing has gotten worse really symptoms just remained the same (I would have done something sooner but a few months after buying the car business tanked and I went broke so I'm in school now.) What are my options and what should I do?

I've searched around but have had trouble finding any concrete answers while searching from google or in forums.

 

scan live data, do a TPS sweep via digital data, not graphing. look at the fully closed/ & wot percentages , and the calculated engine load. If the engine load changes at idle, the physical throttle pos. and the assumed throttle pos. don't agree. Also, PRNDS illumination w/ po706 usually direct us toward the trans range sensor, accompanied by limp mode. If the conditions you have are happening with low oil pressure, the turbo is probably suffering damage and restricting air flow. low oil pressure can also cause the "closed loop" system to kill the fuel pressure. (fuel pump) be analytical, but use a flow chart of some kind to document your findings, and you will find your fault.

 

Similar to my daughters 2006 A4 2.0 CVT. PRNDS flashed off and on for over a year without going full into limp mode. P0706 code would come and go and MIL lit. No real drivability issue but in CA if MIL is lit it won't pass smog for registration. So, with 115,000 on the clock it was time for a timing belt kit anyway and took it out of service for a few weekends. TCM is not easy access, but removal and install not as difficult as manual and forums led me to believe. Refill of trans is tricky but Snap On has the fill adapter for under $20. The adapter, a fluid pump, and an infrared thermometer worked fine to avoid a costly dealer visit for level check. Chose Module Repair Pros in Van Nuys since 40 miles away and could drive it in and check them out first. $350 and turned it around in a day. Only 1,000 miles so far but code, MIL lit gone, and passed smog yesterday. Would recommend Module Repair Pros (www.modulerepairpros.com). Also do ABS and other modules but have no experience with them on those. Good luck, the TCM is a big ticket item from a Dealer.