95 STS Defective ECM (52) & Internal ECM problem (109)

1995 STS - has had problems with engine quitting and now a hard shifting problem in all gears...

Getting both the 52 code error and the 109 code for the ECM and the Internal ECM respectively.. The ECM should be easy enough to find but where is the Internal ECM located?
Best to get new?? replace both?? Thoughts... Thankx

Gave up and took it in to have the repair done.. Reman ECM.. Reprogrammed at the shop.. Runs great.. No longer have hard shifting but still hard to start and that proly is the fuel pump pressure issue... $333

and for future reference, the ECM is located under the dash on the pass side