Hill decent assist

[beetle]

Is there a way to permanently disable this feature? On 2 occasions it has activated when descending a long grade, I'll look down at the tach and it's reading 2500-3500 rpm. Then it shows a message to "dismiss" which I do but it remains activated so I need to manually hold the tow/haul button to deactivate. Absolutely hate this feature, I'm perfectly capable of operating the truck on my own, thanks.

[Trackermi]

Is there a way to permanently disable this feature? On 2 occasions it has activated when descending a long grade, I'll look down at the tach and it's reading 2500-3500 rpm. Then it shows a message to "dismiss" which I do but it remains activated so I need to manually hold the tow/haul button to deactivate. Absolutely hate this feature, I'm perfectly capable of operating the truck on my own, thanks.

There should be a button above the ac outlet that shows a tach and a hill. That will disable it, but I am not sure if it does in tow only.. Have never had to look that far

 

 

Sent from my iPad using Tapatalk HD

[beetle]

There should be a button above the ac outlet that shows a tach and a hill. That will disable it, but I am not sure if it does in tow only.. Have never had to look that far

 

 

Sent from my iPad using Tapatalk HD

I've seen that switch on other trucks but mine doesn't have one.

[Trackermi]

I've seen that switch on other trucks but mine doesn't have one.

Weird, do you have an off-road package?

 

 

Sent from my iPad using Tapatalk HD

[beetle]

Weird, do you have an off-road package?

 

 

Sent from my iPad using Tapatalk HD

No, just an SLT.....I'll re-read the owners manual, maybe I missed something.

[beetle]

Correction, mine is called "Tow/Haul Grade Braking" according to the manual, no provision to shut it off permanately, brilliant!

[MikeNH]

You'll have to hold tow/haul each time to disable it.

[2016 Sierra Owner]

My truck only does what you are talking about when use the cruise control. Is yours doing this all the time? It uses the breaking action to stay at the set speed. If cruise is not activated there is no set speed for it to control to.

[TJay74]

My truck only does what you are talking about when use the cruise control. Is yours doing this all the time? It uses the breaking action to stay at the set speed. If cruise is not activated there is no set speed for it to control to.

 

 

OP is talking about the Grade Braking feature, it was added this year to the trucks. As said no way to turn it off permanently as it was included as a safety feature.

[Trackermi]

So there is a hill descent control and a grade braking? I ask because I have a button on my truck that comes with the off road package that says hill descent control. I'd like to know more cause I find it useless in Michigan and hard to test when there are no hills aroubd

[MikeNH]

So there is a hill descent control and a grade braking? I ask because I have a button on my truck that comes with the off road package that says hill descent control. I'd like to know more cause I find it useless in Michigan and hard to test when there are no hills aroubd

The HDC is part of the Z71 package. Read your manual for how to use it because it's not really meant for on-road use.

[Silverado-Hareek]

So there is a hill descent control and a grade braking? I ask because I have a button on my truck that comes with the off road package that says hill descent control. I'd like to know more cause I find it useless in Michigan and hard to test when there are no hills aroubd

Yes two separate features. Grade braking is a feature to maintain vehicle speed going down grades by downshifting the transmission and using the engine to keep from accelerating when going down a hill or a mountain or whatever. This is turned off by holding the tow/haul mode button for 5 seconds and the same process to turn it back on. When you shut the engine off and turn the vehicle on again, this system is automatically re-enabled since, as others have stated, there is no way to disable it permanently. You have to turn it off yourself every time you want it off.

 

Going by memory, hill decent control is used for speeds under 35 mph and uses the transmission as well as the vehicle braking system to maintain speed going down hills when off roading. So if you were giving it gas going up hill, without this feature the driver would usually switch to the brake pedal after reaching the top of the hill to keep the vehicle from accelerating when you come down the hill on the other side. It basically is a convenience feature so you just have to worry about controlling the gas pedal and steering rather than braking too. This feature is what's controlled with the switch under all of your radio and climate controls. It's next to the bed light switch on my truck.

 

The manual explains all of this in greater detail.

[2016 Sierra Owner]

 

 

OP is talking about the Grade Braking feature, it was added this year to the trucks. As said no way to turn it off permanently as it was included as a safety feature.

 

Yes I know the difference in the 2 features. I don't have Z71 or 4x4 on my truck. There is a small grade on the way to my house. If I have the cruise control set at 55 and hit this grade the speed will rise. To counter act that the transmission will down shift and try to hold the truck at the 55 set point. However if I don't have the cruise control set and just using the gas pedal. The truck will pick up speed like I am coasting and it never downshifts like when the cruise control is on. So I asked if the OP is having this problem with the cruise set or not. Since it seems the system does not operate when not using cruise control.

[beetle]

The "Tow - Haul Grade Braking" on my truck engages with the cruise control off on a long downhill descent.

[fondupot]

The "Tow - Haul Grade Braking" on my truck engages with the cruise control off on a long downhill descent.

 

 

I think what you are noticing is something these trucks do. Basically when coasting down a hill, then fuel supply will be shut off while coasting. So the speed of the wheels are driving the motor. This might feel like its "grade braking" but its not, its a fuel saving feature and has been discussed in another thread. If you shifted into neutral, you would find that the truck freely coasts down the hill. But while in drive, it uses the wheel speed to control the coasting of the vehicle and keep the engine driving so that when you do reengaged the gas, it doesn't have to rev up.

 

Make sense?

 

This can be tuned out with a custom tune. As simple as turning on/off a value in the PCM/TCM

 

*EDIT*

Found it:

 

 

It's called "deceleration fuel cut off" or DFCO. Cuts fuel and timing after certain criteria are met in the ECU, causing the slight engine brake that you are feeling.

 

 

from this thread: http://www.gm-trucks.com/forums/topic/160536-question-regarding-transmission-behavior/