2015 GMC Sierra Grade Braking

Thompson2008 · June 18, 2021

I need help! I have a 2015 GMC Sierra in normal driving conditions on flat surfaces my grade braking activates when I am not accelerating. I have had it to the dealership several times for this and they have replaced the pcm, brake pedal switch and cleaned some connections. This only worked for short period of time each time. They say the computer shows the brake pedal is being depressed is why it is activating, then they will recalibrate it and good for a week of so. I know I can Deactivate the grade braking by pressing and holding The tow haul button. This works for a while and then the truck will go into a limp mode. The dealership is lost I am lost and any help would be much appreciated

Juan Mendoza · October 19, 2021

I have a 2017 silverado LT plus 4x4 z71 that is having the exact same problem! My cruise control does not work and grade braking is always on. Only thing I have found is how to manually take grade baking off. You hold down the tow/haul button for about 4 seconds and it disables it, however, my cruise control still doesn't work. Before I found out the bypass, It messed up my transmission and had to pay for a new transmission. Because nobody has been able to help with this, I have to disable the grade braking every ignition cycle. Someone has to know the answer to this?

pokismoki · October 19, 2021

try reprogramming the transmission and do a re-learn at the dealer

pokismoki · October 19, 2021

is this a 6l80 or the 8L90

BrianBrianBrian · December 13, 2023

I landed on this topic because I'm experiencing similar problems. When my truck gets up to speed around 40mph it begins to lose power and from what I'm learning everywhere this is what limp mode does. I never get a check engine light other than DIC message saying to service stabilitrak. This limp mode somehow feels like grade braking is being activated.

The only code from the OBD is C0161 - ABS/TCS brake switch circuit malfunction.
I've ordered the part and plan to replace the part, but for some reason my spidey sense are not optimistic that this is the cause of my limp mode.