Got my 2018 silverado about a month ago, I keep it lock in a garage at night, with the keys in the ignition. Tried to remote start it with the onstar app and kept getting the "your engine did not start" on my phone. Remembered it won't remote start with the keys in the ignition. BUT it will lock the doors and KEEP them locked, even with the keys in the ignition. At least the app would still unlock the door.