2018 Suburban Premier wont program new key

[Charles Bolon]

I am unable to get my 2018 suburban premier to enter programming mode for they keyfob. I have followed all the tutorials online for programming a new fob with no luck. I only have 1 working keyfob so I have been using those sets of directions. I insert the emergency key into the tumbler, I turn it counter clockwise 5 times and nothing happens. I have tried it with the fob in my hand, I have tried locking the doors first, I have tried it with the door open and closed. I have tried starting the car, turning it off, and then doing it. I have tried it with the car on. I have tried it with the keyfob outside the range of the car with just the emergency key. basically I have tried every variable I can think of that would be causing it to not enter programming mode So I decided to take to to a locksmith to get the fob programmed. The locksmith hooked up their computer to my car and went through the programming process and it didn't work. He tested the key for signal and it was sending signal, we verified I had the right chip inside it and he was stumped. He said maybe the fob I got was bad, but in his career he has only seen that happen once. My worry is that there is something wrong with my suburban. Any help or tips would be greatly appreciated