Buying new truck, few questions.

[Dale99]

I agreed to buy an 08 sierra with the LMM diesel engine. I can still back out if needed, but I'm quite sure I will go thru with it unless this thing is just hosed mechanically.

I am wondering what are some key things to look at engine wise since I am new to diesels?

Also, I didn't see in the listing that the truck had keyless entry, but I swear it has everything else including the kitchen sink Is the code for that "AU0"?

Another, can diesels have remote start? That was a nice addition I added to my current gas truck.