So if it goes below -20C the car will crank but not start. if it does start (happened a few times) it will start run like normal and then just die.
codes that come up when it warms up and it starts are as follows
P0606, P2106, P02105, U01PP
I feel it is the ECU but wanted a few opinions

It would be nice to look at freeze frame data. You have throttle codes that are causing the system to shut down or go low power but the U code I think is not valid. Maybe it'* U0100. I think you have a wiring issue. Verify the codes and see if you can get the freeze frame data.

If I had that and couldn't get the freeze frame data, I'd grab another throttle body and try it.

Moved this thread from "Pontiac Bonneville" to "Pontiac".

Update was -19C and i drove several blocks and it just died without warning :(
unfortunately i dont have the data to be more specific but i will try the throttle body later this week

TB is worth a shot if you are going to shotgun parts at it that'* the place to start.

Agree.

well it works so far although we havent had any bad weather so i guess we will see next winter lol

So . . . you put a new throttle body on it?

More often than not, it'* A WIRE/CONNECTION PROBLEM RATHER THAN THE THROTTLE BODY....

We are talking about the TAC system.......could be throttle body assembly, PPS, ECM/PCM, or any of the wiring or connections in between them....