2016 Silverado 5.3l 1500 “Service Brake Assist”

xch4s3 · May 16

(101,568 miles currently.)

My truck fell under the brake issue/recall. Took it in to a Cadillac dealership back in July 2023 (can’t remember the mileage at the time). Got the truck back and I noticed it felt like ABS would kick in at slow speed stopping, and the pedal would get hard quick. Did some research, and found out GM’s first shitty bandaid “fix” for the recall was to reprogram the brake control module. I’m finally getting around to taking care of my brake problem, and called the dealership, and they confirmed they reprogrammed my brake control module in July 2023. That was it. And it didn’t solve anything. What is the best move going forward? I found a video on YouTube which talks about a service bulletin PIT5361D Diagnostic Tip, https://static.nhtsa.gov/odi/tsbs/2018/MC-10145479-9999.pdf

published on September of 2018. It states the following, “When following the SI diagnostics chart for "Brake Pedal Excessive Effort" it may lead to the "Brake System Vacuum Source Test". While performing this test, if low vacuum is found, inspect the vacuum pump belt. If no belt issues are found, suspect a faulty vacuum pump.
If the vacuum pump is found to be at fault, inspect the vacuum line and brake booster for the presence of engine oil.
IMPORTANT: The vacuum pump is belt-driven and mounted to the side of the engine block and is lubricated by pressurized engine oil.
If NO engine oil is found, then ONLY replace the vacuum pump itself.
If engine oil is found, it is important that the following parts are replaced. If not, the condition will return.
1. Vacuum Pump
2. Vacuum Line between the booster and the pump

3. Brake Booster
4. Master Cylinder

So what’s my best option? Should the Cadillac dealership that reprogrammed my brake control module reprogram it to stock and replace the necessary parts according to this service bulletin? I read in the comment section that I should theoretically be covered still as I’m under 150,000 miles, and my truck gives a message stating “service brake assist.” Or will they not do this necessary test/inspection and not replace the correct parts? Am I better off following this service bulletin myself and biting the bullet replacing everything necessary myself? If so, what do I do about the reprogrammed brake control module? Can I reprogram that myself? Or is it best to request they reprogram it to stock if I replace the parts? Or can it stay in its reprogrammed state either way and not be a problem? Hopefully that wasn’t too hard to follow. Highly appreciate any and all advice/input. Thanks (off the bat I told them I have the service brake assist message popping up, and they said it would be $140 for them to just take a look at the truck before fixing anything. Should I find a different dealership to do the correct fix? Or again; do it myself? But then I still have the reprogrammed brake control module.

also, will disabling DOD/AFM affect this brake vacuum issue?

Edited May 16 by xch4s3

mikeyk101 · May 17

In my case, after experiencing brake problems, the dealership did the "reprogram" under the recall. It worked at first but within a year, problem was back and they replaced the vacuum pump, also under warranty. Don't get too caught up in the whole procedure. If first "fix" didn't work, they need to replace the vacuum pump, simple as that. No, they don't need to unprogram the "fix" first. Just let them do it. The $140 fee is just a diagnostic fee and normal for them to tell you they charge it. They don't require you to pay upfront, it will be charged to you if they fail to find the problem or it ends up being a different problem that isn't covered under warranty (highly unlikely by what you describe) But... If it is a warranty item that neede fix/repair, the diagnostic fee goes away and you owe nothing.

And no, the brake problem is completely unrelated to DOD/AFM.