Would pressure washing my trek deck void my warranty at all?

I would never advise pressure washing a deck, If for somereason you just have to, use lower pressue, less than 2000 and always use a very wide spray, a 30 degree or a 45 degree. Most non professionals do a lot of damage every year to decks pressure washing them.

In general low pressure and the right chemicals will do you a much better job. ( and a little more phsycial cleaning over the pressure

Yes it is fine to power wash your trek decking, they also recommend using a thomsons deck wash when you do, this will bring back the color also.
If this was a wood deck its also OK to do, but you need to have the right tip on the washer before you start,

The tip you need can be just a general purpose tip, avoid anything that shoots a straight beam of water, you want more of a fan type pattern.