Quote Originally Posted by avguy View Post
There is a plug wire (COP) recall for the '09. If those COPs have not been replaced yet on your Aveo, that would tend to explain the performance issues its been having. Also, check the wiring for the O2 sensor first, especially at the connectors. If no wiring problems are found, replace the sensor. Do not do anything related to the transmission until after the O2 sensor issue is fixed, along with the COP recall swap (if not already done). It would not be surprising at all to see the tranny codes and limp mode go away once the engine problems are resolved.
What is this cop plug wire you speak of