The day I drove mine off the lot it threw a code for a sensor in the exhaust, it was replaced 2 days later. This was late February. It has always driven the same way in regards to its downshifting for speed control. It will do it in normal mode if i am repeatedly on the brakes. Happens much quicker in tow haul.
Mine was built 12/19. It doesn’t do that. My grade braking doesn’t come on in normal driving unless I’m really on the brakes. In tow haul it activates much quicker. Maybe you aren’t getting a response because others aren’t having the same issues as you.
Mine went in today for complimentary oil change and tire rotation. I have a little over 6k miles. I let them know about the noisy brakes and tech bulletin. Service adviser asked me if they do it hot or cold, I said mainly hot. Mine get substantial worse after unhooking from my 24’ enclosed trailer. I will let you guys know what they do later today.
I buy them from EBay, you can get a set of 4 for very little money. They work great, run them in my trailers and other car that has 2 full sets of wheels.
Make sure it’s fully closed, I have a GMC multipro and if it’s not fully latched it won’t open, won’t even try to open. I have to push it in and make sure it’s latched fully, then it works fine.
Looks like the end date for Bulletin #20-NA-020 is September 1st of 2019 production. Mine was built in December of 2019 and the brakes squeal, sounds like only the fronts, 5,700ish miles and has been doing it for the last 5-700 miles.
I run generic 433mhz sensors in mine, never had a issue. Less than $30 for all 4 on eBay. Maybe some states use a different metal for their license plates. Do you have a metal trim ring on yours? Try taking it off if so. Does your state offer/make plastic plates? I also have a TPMS relearn tool, makes GM tire rotations a breeze and is helpful with the trailer tpms now that I have them. EL-50448 tpms relearn tool, was $8.50 on ebay.