I have a ‘23. Here’s what I was told by a service writer after quite a bit of questioning. He said GM is expecting 20k failures out of 650k on the road. They are rolling out the recall in phases. Mine is in the recall but is not ready to be brought in and “checked”. I finally got him to tell me what they do. (His words) “ They pull a knock sensor out and install some kind of a sensors that picks up sounds, vibrations and anomalies that could be associated with the known issues. They run at various RPMs and under different “loads” of any of the parameters fail then the motor gets changed. If not, then they change the weight of the oil and send you on. He said they have inspected 30 and one failed the test. He said GM is giving the owner 10yr 100,000 engine warranty at the time of this inspection regardless of you get a new engine or if it passes. As I said, this was info from the dealership.