Why is my engine overheating and engine idling up and a/c off

Hello, In the case of a repair that does not solve the issue, the vehicle should be returned to the dealership. This CTS is in "Limp Mode" to protect itself from overheating. This is normally because the engine coolant temperature (ECT) sensor has informed the engine control module (ECM) that the engine is too hot. Every technician knows to make sure the readings from the ECT are accurate before digging into coolant system components, especially when there is no other symptom besides the temperature gauge rising. Test the ECT, and likely have it replaced to solve this issue. Of course, this could be a mechanical failure, but the technicians should have ruled out other mechanical failure possibilities before rolling your CTS out of the bay door.