Just throwing in my 2 cents here (as another Tiptronic owner)... (not an expert though)...
First, if you are planning to change the fluid and filter, be sure to follow the procedure from the 101 Boxster Projects book (the procedure is also available as an article on the Pelican website - you just have to find it).
Be SURE to use ONLY Pentosin ATF-1 fluid. It's the original factory fluid, and if you use anything else, you might be asking for trouble. For a standard fluid dump, filter change, and refill, you'll need around 5 liters of fluid. When I changed mine I bought the 5 liter size from Amazon. Currently listed as $69.21 USD. (see attached picture)...
You'll need a few extra tools to do the job... a fluid pump (to refill the transmission) and an infrared thermometer to tell when it's at exactly the right temperature. Plus some hex and Torx bits you might not already have. The tools you need are spelled out in the Pelican article.
Your remote will stop working after about 5 days and you will have to use your key to enter the car. The car does this to conserve battery power.
Also, most generic code readers will only talk to the engine computer. It usually takes a Porsche specific tool (like a Durametric or Porsche factory scan tool) to communicate with the other computers in your car (like the transmission, ABS system, A/C system, IP, etc). Hooking up a generic scan tool (or an app like Torque) is not going to talk to the transmission, and that's what I think JFP was talking about when he said you need to read the codes. You need to read the transmission fault codes. The reason you aren't seeing any fault codes is because what you have is only capable of talking to the engine computer.