AT4 service brake assist

[Cpl_Punishment]

I thought I read on here that these trucks have a different brake system design that doesn't have a master cylinder? 

[aupanther33]

On 3/4/2020 at 3:50 PM, Not happy Chevy said:

Swapping me out with a new truck.  Picking it up on the way home.  While I appreciate the swap, this still leaves a bad taste in my mouth regarding the quality of the product.  I sure hope this was just a freak thing,

Mine has been in the shop since Friday morning, got into it for the first time Thursday night and got the Brake Assist message and the CEL. My dealer tracked down a master, but I still don't have it back. Going there now to either get a new or mine back, been driving a Buick Clown car for almost a week. How much push back did you get from the dealer? Thanks

 

[so-cal]

I bought a 2020 Sierra Elevation 5.3L with 24 miles on the odometer on 05/26/2020 - the “Service Brake Assist” message appeared the moment I turned it over to leave the dealer lot around 9 PM that night. 
 

During the test drive earlier that late afternoon I noticed that I had to apply more pressure than normal when coming to a stop, but figured the rotors were coated a bit from production. I didn’t initially start the truck before the test drive, so I don’t know if the dealer saw the message and cleared it while pulling it out of the lineup. 

 

Brought the truck to my closest dealer two days later (when they could fit me in) - they applied two software updates (I don’t have the details, as the paperwork is still in the truck at the dealer). Same message occurred the following morning (Friday, 05/29) - it’s been there since waiting on a master cylinder.

 

The dealer gave me a small Cadillac 2.0 turbo SUVish thingy as a loaner for the time being. I’m not impressed. My 2007 GMC Sierra 4.8L extended cab was great for the past 13 years (with only 73,865 miles on it when I sold it) - I never had issues like this.

 

Unsure what’s going to happen next...and when. Disappointing to say the least.