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Hill descent control

joshc64311

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joshc64311 Enthusiast

joshc64311

Posted
Posted

I had a truck full of firewood and when going down the 20% decline (according to the off road page in the DIC) the truck was crawling 1-2 mph with very little input from me. I have the rally 2 I didn't think it had the hill descent option. so is this standard?

LongrangeLauber Senior Enthusiast

LongrangeLauber

Posted
Posted

20%? That's really steep. Isn't the steepest road grade in the US like 8% (I realize you did say offroad, lol)? As far as your question, I have no idea. I have a High Country and don't even have an offroad page haha

20%? That's really steep. Isn't the steepest road grade in the US like 8% (I realize you did say offroad, lol)? As far as your question, I have no idea. I have a High Country and don't even have an offroad page haha

15 Z71 Senior Enthusiast

15 Z71

Posted
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I think you only have hill descent if you have the z71 package. I have it on my truck,but never have used it. Not really sure how it works.

joshc64311 Enthusiast

joshc64311

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yes its really steep, its a pipe line they put in a few years back with drainage channels that run across it. so as I came over the 1st channel I kinda double tapped the brake and it held the very low speed with the bed full of wood, if I had to guess it was close to a ton+or- real weight so for it to hold the speed is pretty good I think. so a nice little Easter egg I found!

newdude Senior Enthusiast

newdude

Posted
Posted

I had a truck full of firewood and when going down the 20% decline (according to the off road page in the DIC) the truck was crawling 1-2 mph with very little input from me. I have the rally 2 I didn't think it had the hill descent option. so is this standard?

 

 

Mine kicks on automatically when on a steep hill....I have a 16 All Terrain

 

Hill Descent Control is not an "automatic" system. It is Z71 only, and is activated via a toggle switch in the center stack bank (to the right of the cargo lamp switch).

 

The hill descent control system allows a smooth and controlled hill descent in rough terrain without the driver needing to touch the brake pedal. The vehicle will automatically decelerate to a low speed and remain at that speed while activated. Some noise or vibration from the brake system may be apparent when the system is active. The descent control system may be activated, if equipped, by pressing the button on the console. To activate, press the button when traveling at speeds less that 50 km/h (30 MPH). To deactivate, press the button on the console, the brake pedal, or the accelerator. Descent control enables the vehicle to descend using the ABS to control each wheel's speed. If the vehicle accelerates without driver input, the system automatically applies the brakes to slow the vehicle down to the desired speed

 

What you may have experienced is Powertrain Grade Braking

 

ACTIVATION

  • Normal mode powertrain grade braking defaults to "ON" after each ignition key cycle.
  • To disable or enable all grade braking within the current ignition key cycle, press and hold the Tow/Haul button for three seconds.
  • No grade braking is available in Range Selection Mode (Manual Shift Mode).
  • For grade braking to activate it requires the driver to apply steady brake pedal pressure to maintain desired speed while driving on a downhill grade. The vehicle's modules monitor the amount of brake pedal apply, vehicle deceleration rates, and other factors to determine if normal mode powertrain grade braking is necessary. When the feature activates for the first time that ignition cycle, the DIC will display "Grade Braking On" or "Grade Braking Active" and you will notice the transmission down shifts and engine RPM increases. At this point, if the brake pedal is released the transmission will hold the current gear. If additional engine/transmission braking is needed to help maintain desired speed, reapply steady brake pedal pressure and additional down shifts may occur.
  • Normal mode powertrain grade braking will have a less aggressive transmission down shift schedule than Tow/Haul mode powertrain grade braking.
  • Grade-braking can be exited by depressing the accelerator pedal.

 

ruggerag Enthusiast

ruggerag

Posted
Posted

20%? That's really steep. Isn't the steepest road grade in the US like 8% (I realize you did say offroad, lol)? As far as your question, I have no idea. I have a High Country and don't even have an offroad page haha

20%? That's really steep. Isn't the steepest road grade in the US like 8% (I realize you did say offroad, lol)? As far as your question, I have no idea. I have a High Country and don't even have an offroad page haha

You should be able to go into your settings for the driver screen and add the page in or remove pages you don't want. Had a buddy who said he didn't have the screen but turns out he just hadn't turned it on.

Tattooo Senior Enthusiast

Tattooo

Posted
Posted

 

 

 

Hill Descent Control is not an "automatic" system. It is Z71 only, and is activated via a toggle switch in the center stack bank (to the right of the cargo lamp switch).

 

 

What you may have experienced is Powertrain Grade Braking

 

It is automatic when turned on the same way parking sensors are once turned on ?
newdude Senior Enthusiast

newdude

Posted
Posted

It is automatic when turned on the same way parking sensors are once turned on ?

 

I would lmagine so but HDC is speed sensitive.

The HDC light displays on the instrument cluster when enabled.

HDC can maintain vehicle speeds between 3 and 22 km/h (2 and 14 mph) on an incline greater than or equal to a 10% grade. A blinking HDC light indicates the system is actively applying the brakes to maintain vehicle speed.

When HDC is activated, the initial HDC speed is set to the current driving speed. It can be increased or decreased by applying the accelerator or brake pedal. This adjusted speed becomes the new set speed.

HDC will remain enabled between 22 and 60 km/h (14 and 37 mph); however vehicle speed cannot be set or maintained in this range. It will automatically disable if the vehicle speed is above 80 km/h (50 mph) or above 60 km/h (37 mph) for at least 30 seconds. 5 must be pressed again to re-enable HDC.

When enabled, if the vehicle is at a speed above 22 km/h (14 mph) and less than 60 km/h (37 mph), a DIC message will display

 

 

Now say you are going 60mph down a grade, and you lightly feather your brake pedal for a couple of seconds, you would experience the powertrain grade braking (which works like cruise control grade braking but with cruise off). If HDC is off, powertrain grade braking is always on (engine compression braking and trans downshifts to slow). HDC is via the ABS system.

joshc64311 Enthusiast

joshc64311

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I would lmagine so but HDC is speed sensitive.

 

Now say you are going 60mph down a grade, and you lightly feather your brake pedal for a couple of seconds, you would experience the powertrain grade braking (which works like cruise control grade braking but with cruise off). If HDC is off, powertrain grade braking is always on (engine compression braking and trans downshifts to slow). HDC is via the ABS system.

that's what makes me think its HDC because grade breaking is speed sensitive, example on mine it wont kick in under like 15mph. now when I was going down the hill in 4 low at idk 1-2mph the truck needed very little input from me to maintain that speed, when I got to the bottom and taped the gas it felt like the breaks were released and the truck lunged foreword. I find it odd that grade breaking would work wile the engine is at idle and truck speed is under 5mph.

Justin5352 Enthusiast

Justin5352

Posted
Posted

I have a 2015 CC LTZ 4x4 non Z71 and I'm pretty sure I have been at a red light on a slight incline holding the brake and when I let off the brake I have seen in the DIC it wil say Hill Descent Control Activated. So what's that all about?


I have a 2015 CC LTZ 4x4 non Z71 and I'm pretty sure I have been at a red light on a slight incline holding the brake and when I let off the brake I have seen in the DIC it wil say Hill Descent Control Activated. So what's that all about?

LongrangeLauber Senior Enthusiast

LongrangeLauber

Posted
Posted

I have a 2015 CC LTZ 4x4 non Z71 and I'm pretty sure I have been at a red light on a slight incline holding the brake and when I let off the brake I have seen in the DIC it wil say Hill Descent Control Activated. So what's that all about?

 

I have a 2015 CC LTZ 4x4 non Z71 and I'm pretty sure I have been at a red light on a slight incline holding the brake and when I let off the brake I have seen in the DIC it wil say Hill Descent Control Activated. So what's that all about?

It actually says Hill Start Assist Active, or at least it should lol. I get it at the only stop light on my way to work every morning
joshc64311 Enthusiast

joshc64311

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It actually says Hill Start Assist Active, or at least it should lol. I get it at the only stop light on my way to work every morning

yes I think that's to keep the truck from costing backwards of forewords from a stop

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