2007 Yukon XL Denali No Start - Not Battery and likely not starter

[The XL]

Need help.

Dec. 30, had to have vehicle towed to shop for no start and couldn't be boosted. Said it needed battery and starter. Did both.

Jan 2, had to have vehicle towed to shop for no start and couldn't be boosted. Said starter was faulty, replaced starter.

Jan 15, had to have vehicle towed to shop for no start and couldn't be boosted. Initially said faulty starter, then said, oops, nope, just need brass nut.

Jan 22, had to have vehicle towed to shop for no start and couldn't be boosted. HELP!!

 

Any ideas? Passkey? Computer? Neutral switch?

[Duelin]

I hate to say this but I would be looking for another repair shop or mechanic. I doesn't take too much to diagnose a battery or a starter.

[The XL]

we've replaced both. It's at the dealer.

[Doug_Scott]

What does "couldn't be boosted" mean?

 

There are two parts to starting an engine. First is the engine cranking over by the starter, second is engine continuing to run when key is let go. Need to know if engine is cranking over.