Hello,
I too am having this problem on my 2023 sierra 1500 SLT. The dealer says they can’t find anything but it has happened twice already. I’ve opened a claim and they tell me that the dealer said they didn’t find any codes but I personally was able to pull the codes, so I know they exist. In addition to this the service woman that received my truck that day said some codes were showing. This is a huge safety concern and the loss of braking is no laughing matter. Their attitude towards the situation is unacceptable in my opinion. Customer service at GM said there is nobody to escalate this situation to. Please give me some direction on where to go.