Hill Decent Control

[Norcal Flyfisherman]

I used HDC last weekend on a long steep dirt road. After about a mile I got a message that said "Service Stabillitrac", then the HDC turned off. I hit the switch again and it seemed to work fine, but that could have been a bad spot for that to happen. No other alerts or messages since.

[chuckwi11]

I was pulling a trailer today (moving to Dallas/Fort Worth) and as I was slowing down the truck abruptly downshifted and rev'ed... freaked me out! The second time it did it I noticed the Grade braking or whatever message... it revs pretty high as it downshifts! I was going to call BB and ask if they mod'd the trailering shift... glad I saw this thread.

[bdbake01]

I was pulling a trailer today (moving to Dallas/Fort Worth) and as I was slowing down the truck abruptly downshifted and rev'ed... freaked me out! The second time it did it I noticed the Grade braking or whatever message... it revs pretty high as it downshifts! I was going to call BB and ask if they mod'd the trailering shift... glad I saw this thread.

 

You're describing the "Grade Braking" feature, not the Hill Descent Control, two different things. But, yes that's normal, and once you get used to it you will really like it while trailering. It won't hurt the engine or tranny.

[Lawnmower2020]

Great thread on this, with special thanks to bdbake01 for helping sort it out. I'm getting my '14 next week and have been fairly confused about the Grade Braking and HDC based on reading the "for idiots" Owners Manual.

 

I'm trading a 2011 LT-Z71 on this 2014 LT-Z71 (they made me a deal that no sane person could have refused). The 2011 has no provisions for assisted hill descending other than the brake pedal and the manual transmission downshift with pushbutton selection of some lower gear. From what I'm understanding now, the Grade Braking can perform the downshift automatically. Is that feature always-on? If not, how is that enabled? What sets its "target" speed?

[Ventilator]

Great thread on this, with special thanks to bdbake01 for helping sort it out. I'm getting my '14 next week and have been fairly confused about the Grade Braking and HDC based on reading the "for idiots" Owners Manual.

 

I'm trading a 2011 LT-Z71 on this 2014 LT-Z71 (they made me a deal that no sane person could have refused). The 2011 has no provisions for assisted hill descending other than the brake pedal and the manual transmission downshift with pushbutton selection of some lower gear. From what I'm understanding now, the Grade Braking can perform the downshift automatically. Is that feature always-on? If not, how is that enabled? What sets its "target" speed?

 

 

There is a switch on the dash/console, and you have to be going fairly slow to engage it. Not sure the exact speed but I think it is somewhere around 15-20 MPH. I know it will warn you to slow down to engage if you are going too fast.

[thefishhawk]

 

 

There is a switch on the dash/console, and you have to be going fairly slow to engage it. Not sure the exact speed but I think it is somewhere around 15-20 MPH. I know it will warn you to slow down to engage if you are going too fast.

That's the hill descent, not the grade braking. On grade braking it senses how steep the hill is and in tow/haul mode if you tap the brakes it downshifts to help you hold speed without using the brakes.

[MikeNH]

Great thread on this, with special thanks to bdbake01 for helping sort it out. I'm getting my '14 next week and have been fairly confused about the Grade Braking and HDC based on reading the "for idiots" Owners Manual.

 

I'm trading a 2011 LT-Z71 on this 2014 LT-Z71 (they made me a deal that no sane person could have refused). The 2011 has no provisions for assisted hill descending other than the brake pedal and the manual transmission downshift with pushbutton selection of some lower gear. From what I'm understanding now, the Grade Braking can perform the downshift automatically. Is that feature always-on? If not, how is that enabled? What sets its "target" speed?

 

Grade braking is always on I think and I believe you can disable it by holding the tow/haul for several seconds. Hill Decent Control works at low speeds, pretty sure it'll hold the speed you're at when you push the button below the radio/HVAC controls.

[Ventilator]

That's the hill descent, not the grade braking. On grade braking it senses how steep the hill is and in tow/haul mode if you tap the brakes it downshifts to help you hold speed without using the brakes.

 

 

Yes, you are right. I had the thread title in my mind. Had I read the post above his, I might have snapped out of it. Then again, maybe not.

 

Thanks for clearing that up.

 

 

[Norcal Flyfisherman]

I've used the hill descent several times, and it works great for short, steep hills. I have had it turn off on its own though, not a great feeling on a rocky hillside. Has anyone else had this experience?

[Sicmab]

Yikes... So it's been a while since there's been some activity. Does anyone know if this feature can be added? I know it works in tandem with ABS so I imagine maybe a module + programming, and a control switch swap on the center console?

[Jay700]

I have it and don't use it I think it's pointless.

[Sicmab]

So there goes my idea about adding the z71 package. Spoke to Chevy and HDC is built in. Can't rig this once the truck has left the factory.

[redwngr]

Hill Descent

Control (HDC)

If equipped, HDC can be used when

driving downhill. It sets and

maintains vehicle speed while

descending a very steep incline in a

forward or reverse gear.

The HDC switch is on the center

stack, below the climate controls.

Press 5 to enable or disable HDC.

Vehicle speed must be below

50 km/h (31 mph).

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. See Vehicle

Speed Messages on page 5-45.

[EXSlider400]

ACTUALLY....

 

I think we are discussing 3 distinct things here.

 

One is Hill Start Assist, and it's just what it sounds like, it holds the brakes for up to 1.5 seconds while facing uphill or until you hit the gas. Keeps you from rolling back. I would say this is handy, and it probably is, but where was this in the days of a manual slush box???

 

One is Grade Engine Braking (really not sure of the name, or IF it has a distinct name). Think of it as a cruise control jake brake. It uses the engine to maintain speed downhill, particularly when you have a load. It can rev the engine rather high, you'll know it when it happens. I think this is standard issue on nearly, if not all trims. It works at higher, cruise speeds and doesn't involve the brakes.

 

Last, but not least is Hill Descent Control. Only comes on certain packages, (I know AT has, I think Z71 has as well), and it requires a push of the button. Low speed operation only, think <37 mph or something like that. It's like cruise control for SLOW down hill descents. Uses a combination of engine braking (mentioned before) and conventional braking. Yes, it will apply the brakes FOR you. But, at least you have to actively select this by pushing the button on the console. Do you have it? Well...do you have the button??

This is correct I think. Also, hill decent can apply brake to each separate wheel individually (via ABS hence the noise) for better decent...something a brake peddle can not to.

[bdbake01]

This is correct I think. Also, hill decent can apply brake to each separate wheel individually (via ABS hence the noise) for better decent...something a brake peddle can not to.

 

Correct. HDC uses the anti-lock system to apply braking one wheel at a time. I have witnessed this personally on a rather unstable, steep gravel-ish decline hill and it works magnificently. At first I thought I'd never use, but as it turns out it is rather useful, at least in my line of business. I didn't expect this.