How to Turn on the Engine Brake on a 2020 Freightliner Cascadia

So you just got behind the wheel of a brand new 2020 Freightliner Cascadia. Nice ride! As you’re admiring the sleek lines and spacious cabin, you notice a switch on the steering column that says “Engine Brake.” What exactly does that do and how do you use it? Well, friend, you’ve come to the right place. We’ll walk you through everything you need to know about operating the engine brake in the 2020 Cascadia.

Here’s a quick answer:

To turn on the engine brake in a 2020 Freightliner Cascadia, locate the black dial switch on the steering column below the turn signals. Select Manual mode for the most control or Auto to automatically activate when your foot lifts off the accelerator downhill. Make sure to also press the brake pedal when engaging the engine brake in either mode.

What is the Engine Brake For?

The engine brake, sometimes called the Jacobs brake or compression brake, uses the truck’s engine to help slow the vehicle down. When activated, it opens the exhaust valves at a specific time to cause resistance that helps decelerate the truck. This is extremely useful when going down long declines as it takes some of the burden off the wheel brakes. Using the engine brake prevents overheating and wear & tear on the regular brake system. Overheated brakes lose stopping power, which is downright dangerous when commanding an 80,000 lb truck. So the engine brake plays an important role in maintaining control and safety.

Locating the Engine Brake Switch

The engine brake switch on the 2020 Cascadia is conveniently situated on the steering column below the turn signal arm. It’s a black dial with labels indicating the Off, Manual, and Auto positions. You’ll want to familiarize yourself with the feel and location of this switch so you can operate it without taking your eyes off the road.

Understanding the Positions

Here is what each of the three positions does:

  • Off – The engine brake is deactivated. This is for normal driving when you do not need auxiliary slowing capability.
  • Manual – This allows you to manually activate and deactivate the engine brake whenever needed. You get full control over its operation.
  • Auto – In this mode, the engine brake automatically engages when you take your foot off the accelerator going downhill. It’s a hands-free way to use the engine brake for descent control.

Operating the Engine Brake

Using the engine brake is all about selecting the right mode for driving conditions:

Manual Mode

We recommend using Manual mode whenever possible as it gives you the best control. Here are the steps for operation:

  1. Verify your desired retarding level on the secondary brakes gauge. This lets you select low, medium or high levels.
  2. With your foot on the brake pedal, move the switch from Off to Manual.
  3. The engine brake will activate. Adjust the retardation level as needed for the grade.
  4. To deactivate, press the throttle pedal or turn the dial back to Off.

Manual mode allows you to precisely control brake application and intensity. It’s safest for slippery surfaces so you can back off at any time.

Auto Mode

Auto mode is great for long gradual descents where you want some assistance without constant manipulation:

  1. Verify your descent speed gives adequate stopping distance for the Auto setting to work properly.
  2. Switch from Off to Auto right before the grade starts descending.
  3. The engine brake engages automatically once you lift your foot from the throttle.
  4. It remains active at a factory preset level as you roll down the hill.
  5. Pressing the throttle pedal for even a split second disengages Auto operation.

The Cascadia determines the Auto activation based on road pitch, so beware it may engage even when not intended if the system misjudges the terrain.

Tips for Safe Operation

When employing the Jacobs brake, keep these additional tips in mind:

  • Avoid using the engine brake on slippery surfaces like ice or loose gravel as it could cause wheel slippage.
  • Manually disengage on bridges and in tunnels to prevent noise complaints from the amplification.
  • Use J brake early and often on long downgrades to avoid overheating the friction brakes.
  • Engine braking affects vehicle stability by shifting weight forward. Adjust speed to compensate.
  • The ‘Check Brake’ light indicates a J brake malfunction. Head to the shop for inspection and avoid manual activation before repairs.

Understanding Brake Performance Tables

In your owner’s manual, Freightliner provides brake performance tables to show speed reduction capabilities from mph to mph based on gross weight. It looks like this:

Speed MPHDesired MPH56,000 LBS66,000 LBS80,000 LBS
50400.08 mi0.11 mi0.16 mi
50300.17 mi0.22 mi0.30 mi
60400.12 mi0.15 mi0.21 mi

So for a truck weighing 80,000 lbs descending a 6% grade at 60 mph, the chart indicates you could activate the brake and decelerate down to 40 mph after about 0.21 miles. This helps you gauge required stopping distances. Refer to it when preparing your descent plan.

When to Avoid the Engine Brake

While engine braking provides tremendous benefits for vehicle control, don’t use it in these scenarios:

  • Icy or snow-covered roads
  • Wet leaves or loose gravel where wheel slippage occurs
  • Tunnels or bridges where noise echoes

The amplified J brake noise and potential wheel slip could present safety issues in these situations, so deactivate it until conditions improve.

Let’s Review

Now that you know where the switch is and how to use it, here’s a quick recap on operating the 2020 Cascadia’s engine brake system:

  1. Locate black dial on steering column below signals
  2. Select Off for none, Manual for control, or Auto for hands-free help
  3. Verify retard level on secondary gauge
  4. Use Manual for best results descending grades

Then monitor brake temperatures to avoid overheating. That’s really all there is to it!


We hope this breakdown gives you confidence in using your 2020 Freightliner Cascadia’s engine brake for greater safety and control while out on the open road. Whether you choose Manual or Auto mode, this auxiliary slowing device saves wear and tear on your friction brakes.

Refer to the performance charts to gauge stopping power based on weight and speed. With a little practice flipping that switch, the engine brake will become second nature and make driving in the mountains much less stressful. Here’s to happy engine braking and staying safe out there on the long hauls!


1. Why should I use the engine brake?

Using the engine brake takes pressure off the wheel braking system when going downhill. This prevents overheated and faded brakes which are dangerous.

2. When should I not use the engine brake?

Avoid using the engine brake on slippery surfaces like snow or ice where too much retardation could cause wheel slippage. Also disable in tunnels and on bridges to reduce noise.

3. What’s the difference between Manual and Auto mode?

In Manual mode you actively turn the engine brake on and off as needed. Auto mode engages the engine brake automatically when your foot lifts off the accelerator going downhill.

4. How do I know if the engine brake has a problem?

If the “Check Brake” light comes on, there is an engine brake malfunction that needs to be addressed before manually activating the system.

5. Will the engine brake work if I don’t also use the wheel brakes?

No, you have to apply the wheel brakes for the engine brake to effectively slow the vehicle down. The two systems work in conjunction.

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