Cusser

I don't think GM or most manufacturers will spend a penny that they don't have to.

This way, when you take it in for TSB 17336 repair, the dealer can try to sell you other needed and/or non-needed services at full prices. When we took our 2005 Yukon in to dealer for an intermittent non-closing sunroof, our "laundry list" included need for new radiator hoses and serpentine belt. Any high school drop could've noticed Gates stickers still on the 2-month old radiator hoses I had replaced, and that I used aftermarket hose clamps too. Plus an aftermarket serpentine belt. My guess is that NO ONE even lifted the hood for that list of needed repairs. By the way: dealer was unable to fix our sunroof, told me they "had no idea what was wrong" and after a little fight they did refund my repair money, as they agreed when I said I'd pay for a FIX but not for a guess. So terrible 4-trip experience, and I eventually pulled the sunroof fuse when it "chose" to close one day (it always would open fine).

repairman54

TSB is a service bulletin to aid the techs in diagnosing an issue. Not a safety recall that would be repaired automatically on a CPO or any other used vehicle.
Certified is a reassurance it's clean, accident free and has its original warranty extended by the mileage already on it. I've bought a few CPO's.

Cusser

I should have figured that it wasn't a recall, GM wouldn't fix anything for no cost that they didn't have to. When we bought our 1994 Suburban in 2000, the windshield wipers sometimes didn't work when it rained. In late 1998 and early 1999, GM recalled more than 1.5 million pickups and sport-utilities from the 1994-96 model years to replace wiper motor circuit boards and covers. The company said heat and vibration caused solder joints to crack. Somehow the VIN of OUR Suburban wasn't included in this. GM wanted like $50 and $50 installation of new circuit board - which takes like 3 minutes to R&R; I know this because I eventually removed the circuit board and re-soldered the connections to fix, following the instructions/photos I saw online. Poor engineering and manufacture caused vibrations breaking this, and GM wanted to make money from their error.

GM tried to argue that inoperative wipers were NOT a safety risk.

https://www.autoweek.com/news/a21103...-98-gm-trucks/