300c u0101 issues

So I pickup a 05 300c with 180k.. cat back exhaust, intake,aftermarket deck Ran fine for a week. Then I started getting this code. So have replace the tcm..same problem
So I replace the pcm..same problem
Iv clean and check ever ground I could find.
Now I get codes p0700 and u0101. I know what they mean which Is why I replace tcm, pcm but didn't fix prolem.
Where else should I be looking.. could it be a bad tranns..fluid is dark brown..so someone didn't take care of the car..
Any help out here..
Also I'm the new guy so hello to all..