Slope assist when going down steep long hill...oddity

Arch Angel · October 2, 2017

Hello,

First time posting,

So I had asked the dealership and they seemed confused by this but said it is "hill descent control"...which I don't believe I have as I do not have a switch in the center for that option.

a few weeks back I was going down a long steepish incline on a road not sure actual grade as I was just driving down the side road with the family in the vehicle going out to diner talking. all of a sudden it felt like my engine downshifted and the entire truck started to slow itself down --- I know at that point did have my foot on the brake slowing down for some time, I had looked down at the center console and seen "slope assist" displayed on my LCD display I let my foot off the brake and the truck held my speed around 35 mph without any assistance going downhill ... I was very confused by this. then I just finished my drive to the place.

I called the dealership the next business day and talked to them about this and they just came to the conclusion it had to be hill decent control.... which I don't see I have.

my truck: 2017 Silverado 1500 all-star crew cab short box. 11k miles --

has any one else seen this "slope assist" come up and know what it might be?

Donstar · October 2, 2017

Welcome to this forum. This is a great question. My '09 Sierra would do this occasionally but I thought it had something to do with tow/haul mode as I was usually towing at the time. I haven't noticed this with my '15 Sierra but I haven't done the same type of driving as I did with my last truck. There are some very knowledgeable people on this forum and undoubtedly we'll hear some good answers.

Arch Angel · October 2, 2017

I have noticed the knowledge level here seems to rise up pretty high haha , the dealership seemed to be a bit lost when i asked...so..yah

thank you tho very interesting "option" to have.../not have ? haha

The Tos · October 2, 2017

I had a question on this as well. I have the toggle for this option but never really activate it. I do notice that this feature automatically works when going down larger hills, especially when I am towing my camper. So do I ever really need to manually toggle this on or will the truck always activate it on its on? If so, what is the point of the manual toggle switch?

Nick The Great · October 2, 2017

Slope assist is not Hill Control Descent, right?

Mine shouldn't have the Hill Control Descent (no button either) but every so often I get this Hill Start Assist message. Typically when I'm stopped at this stoplight going up a hill. Mine's just going up a hill, not down, so maybe we're talking two different things.

Can't quite figure it out and it doesn't seem to always show up in this spot either.

sonerick · October 2, 2017

There's some good info on this topic in this thread: http://www.gm-trucks.com/forums/topic/155409-hill-decent-control/

Sierra706 · October 2, 2017

Grade braking is what you experienced. It will kick in on a long sloping grade with enough time spent on the brakes. Putting the truck into tow/haul dramatically shortens the time required to engage. It will downshift to help slow your truck. You can turn it off by holding the tow/haul button for 5 seconds and a notice will appear on your cluster. It will revert back to on next time you start your truck. This is standard on all trucks.

Hill descent control is for slow speed steep declines, and uses the ABS system to keep your vehicle at the speed you set, under 20 or so mph. It’s for off-road situations or for example a very steep and icy driveway. This is an extra included in top trim levels and the z71 package.

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sk · October 12, 2017

On 10/2/2017 at 11:33 AM, Bushleaguechew said:

Grade braking is what you experienced. It will kick in on a long sloping grade with enough time spent on the brakes. Putting the truck into tow/haul dramatically shortens the time required to engage. It will downshift to help slow your truck. You can turn it off by holding the tow/haul button for 5 seconds and a notice will appear on your cluster. It will revert back to on next time you start your truck. This is standard on all trucks.

Hill descent control is for slow speed steep declines, and uses the ABS system to keep your vehicle at the speed you set, under 20 or so mph. It’s for off-road situations or for example a very steep and icy driveway. This is an extra included in top trim levels and the z71 package.

This is 100% correct.

x219c · October 15, 2017

Slope assist is not Hill Control Descent, right?

Mine shouldn't have the Hill Control Descent (no button either) but every so often I get this Hill Start Assist message. Typically when I'm stopped at this stoplight going up a hill. Mine's just going up a hill, not down, so maybe we're talking two different things.

Can't quite figure it out and it doesn't seem to always show up in this spot either.

This is hill start assist. It keeps your breaks on while you get on the gas before rolling backwards. It only engages on hills over a certain grade after coming to a stop. Usually see this in manuals, but it can be helpful while towing, etc.

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cire0309 · October 15, 2017

GRADE BRAKING ACTIVE

This message displays when grade braking has been activated while driving on downhill grades.

Hill Start Assist (HSA)

This vehicle has an HSA feature, which may be useful when the vehicle is stopped on a grade. This feature is designed to prevent the vehicle from rolling, either forward or rearward, during vehicle drive off. After you completely stop and hold the vehicle in a complete standstill on a grade, HSA will automatically activate. During the transition period between when you release the brake pedal and start to accelerate to drive off on a grade, HSA holds the braking pressure for a maximum of two seconds to ensure that there is no rolling. The brakes will automatically release when the accelerator pedal is applied within the two-second window.

I see the Hill Start message on a daily basis. If you're stopped on any kind of a little hill at a traffic light, the message pops up. As for Grade Braking, I've only seen that once when descending a long grade when I was riding the brakes on purpose trying to get Grade Braking to activate. If you coast downhill, the transmission will still upshift and the vehicle will gain speed.

sk · October 16, 2017

It's really confusing! There are actually 4 different things we are talking about that are all available on these trucks:

Hill Start Assist

Holds the truck when stopped facing uphill. When you take your foot off the brake and move to the gas the truck will not roll backwards. Comes on automatically each time you start the truck. It can't be disengaged.

Hill Descent Control

Only for low-speed "rock crawling" type driving (under 13 mph). Actually modulates the ABS for individual wheels to control downhill speed. It is only available on Z71 and All-Terrain trucks. You must press the button in the bank of switches below the HVAC controls to engage it.

Grade Braking (normal mode)

Uses the transmission and brakes to slow the vehicle. It is automatically activated each time you start the truck. You can disengage it by holding the Tow/Haul button in for 5 seconds.

Grade Braking (tow/haul mode)

Same as normal mode above but the shift points are different and the braking is more aggressive.

steve76t · October 17, 2017

Thats what that was. I noticed this on my new 17 Denali & wondered what it was too. Thanks for posting this up and answering my questions before I had a chance to even ask.