Service Brake Assist

[Rdr854]

So after having this problem since last November(NY to Nashville trip) weirdest feeling ever. I brought the truck in to service in Dec. They said nope nothing is wrong after having the truck for 2 days.
Kept coming back at times specially coming out my 100ft driveway in reverse(after it was warm/hot).
So I made another appointment for early today and I made sure I jumped in the highway too make sure it was hot when I got to the dealership. As soon as I got to the service department I asked the guy please don't write it up till I speak to a manager and I told please get a mechanic out here so he can drive it in the parking lot and to see that I'm not crazy.
Finally they did and and replaced the Vacuum Pump. Here is the write up in case anyone needs it. I hope it helps.

View attachment 247993

Mine was a different problem.

 

[AngelXL]

Mine was a different problem.

So you fixed it already?

 

[AngelXL]

Bunch of videos on YouTube on how to replace the pump.
https://www.google.com/amp/s/www.tfltruck.com/2019/09/gm-recall-vacuum-pump-news/amp/

 

[Big Mama]

I’ve got a tug to the left under medium/hard braking. Checking that out this weekend and will check the lines too.

 

[Rdr854]

So you fixed it already?

Yes, a bad brake booster sensor. Replaced under warranty.

 

[Rdr854]

Yes, a bad brake booster sensor. Replaced under warranty.

And, now a year later . . . Guess what. The problem is back and the dealer’s diagnosis is the same — a bad brake booster sensor.

I have asked the dealer to find out the why because I do not want to be coming back on what seems like an annual basis to remedy this problem.

 

[Rdr854]

And again, I had the same problem with the same repair. This is the fourth time. Happened at 7,000 m8les, 11,000 miles, 18,000 miles and now again at 21,000 miles. Same symptoms and the diagnosis is replacement of the sensor each time. I have submitted complaints to NHTSA with no reaction (shock face).

I do not understand why this keeps happening (and quite frankly, the dealer is at a loss too).