Hill Descent Control

Hill Descent Control (HDC) has been available on Rubicon models for quite some time, but most people never use it! 

When to use HDC

It’s a great feature when you are descending a steep hill to focus on the terrain, and let the Jeep keep you at a safe speed. The vehicle controls the speed of descent automatically, using the electronics and components of the traction control system to activate braking maintaining a constant speed and as much traction on each tire as possible.

How to use HDC

In order to use HDC your Jeep must be in a status that will allow it to operate. You must be in four wheel drive low (4L). You should then move the automatic transmission to manual mode. Downshift into first. It’s best to start at the top of the hill or obstacle.

Once you have the requirements in place you can activate HDC by pressing the button on your center dash. It looks like this:

Once activated the HDC light is activated on your display. 

Now that the HDC control is activated you should not touch the brakes. You will hear “funny” sounds as they operate and slow your descent. (You can use your brakes, which will slow the vehicle down to below the specs shown below, but really that’s not the best way).

The JK and the JL models do operate a little differently, but essentially the same. As you are in manual transmission mode, you are now controlling the Jeep’s descent speed with your gear choice alone. 

In first gear you will be creeping down the hill; if you shift up the Jeep will speed up. The JK and JL have different speeds at different gears, as the transmission is not the same in the new JLs.

The difference between the JKs and JLs are shown below:

JK

Gear Approximate HDC Set Speed

1st 1 mph 

2nd 2.5 mph

3rd 4 mph 

4th 5.5 mph 

DRIVE 7.5 mph 

REVERSE 1 mph 

JL

Gear Approximate HDC Set Speed

1st 0.6 mph

2nd 1.2 mph

3rd 1.8 mph

4th 2.5 mph

5th 3.1 mph

6th 3.7 mph

7th 4.3 mph

8th 5.0 mph

DRIVE 0.6 mph

REVERSE 0.6 mph

Deactivate the HDC control by pushing the button on the dash when you have completed the obstacle or descent. The light in the display will go away when it has been deactivated. Don’t forget to put your foot back on the brake pedal at this point!

Performance

We have utilized HDC in just about every scenario you could imagine, and it really does perform well. Slippery rocks, extremely sleep slopes, loose dirt – the Jeep handles it. With new clients, it really can make a difference. The driver’s focus can be much more concentrated on the line, while the Jeeps controls the speed and traction. For more experienced drivers, we would encourage it’s use when you are on new obstacles, or when you want to push the limits a bit.

As you can see above HDC can also be used in reverse, but admittedly the experience is a bit harrowing. There is a lot of trust involved there…

Over the years a few Jeeps have seen brakes overheat while using HDC on long declines, so keep in mind it should be used more to tackle obstacles, than as a downhill “cruise control”.