I have been having all kinds of issues with my ATS 2.0T with check engine lights and things not running right. One of the lights I got was for the cam shaft position sensor. I took it to a mechanic and he determined the sensor was bad because the computer was saying it was giving off low voltage or something along those lines and replaced it. This didn't help, so I took it to the Cadillac dealership, which I probably should have done to start with.
They found that the return hose to the coolant reservoir was leaking. I knew I was losing some coolant, but I would just top it off occasionally. Bad on me, I know. I should have fixed it. This leak is apparently really common with the ATS and Camaro. Unfortunately, the ECU is right below the "Y" in the line that was leaking. This caused corrosion on the bottom connector on the ECU as well as the plug on the harness.
The dealership wanted $2,200 to replace the ECU, splice in new wires to the harness, and repin the connector. I decided to to try to clean the ECU and the connector myself. So far, it seems to be doing much, much better.
I made a video of my adventures with this and figured I would share if with you all in case it might be helpful to somebody else. Moral of the story, fix those daggon leaks...
Here is the video if anyone is interested. I am not a mechanic and if I did something, or say something dumb, please leave a nice comment correcting me for the sake of anyone that views this video. Thanks!