Green Engine Light on Freightliner (What Does That Mean?)

Symbols are shorthand for many warnings and instructions. Modern vehicles come with so many symbols that a driver needs a college course to learn what they all mean. Rigs are no different and when the symbols light up, you got to know what to do next.

Not every rig will have this green engine light but some Motor homes do. All it means is that the jake brake has been enabled. The light will go off when you step on the accelerator again. If it doesn’t, see a mechanic as there may be a short or a problem.

Freightliner Cascadia Green Engine Light


Unfortunately, this situation is not as simple as it sounds. Along with the jake brake enabling, the check engine light could be indicating other problems that are happening under the hood.

One example would be the coolant system. The engine monitors the levels and the temperature of the coolant and if something is amiss, the light will go on. Or the light will come on when the engine cannot do a proper regen.

The real problems will be indicated by multiple check engine lights and a red stop engine light. When that happens the oil pump may be going out and you will need to get the part replaced.

One of the best ways to help yourself when you see this light or other lights appear on your dashboard is to have the owner's manual handy. It will tell you what is going on and what you should do when it does. Sometimes you can keep driving until you get to the nearest town.

Green Engine Light With fan Kenworth


This situation can indicate any number of problems. One source could be the AC and the light is indicating a problem with the switch. or wiring. Or the temperature sensor may not be working well, there is an improper charge in the AC system, ECM software issues, and so on.

Also, there could be no airline going to the mounting bracket that the hub sits on. On top of that, it may be a coolant issue. It is hard to say exactly which issue it would be as many of the possibilities may have the same symptoms.

When this light comes on, and to relieve your fears, talk to a qualified mechanic. They will know what to do. Sometimes the lights come on when there is a simple short. It is hard to say as so much technology has gone into these engines that there will be any number of reasons for these symbols to illuminate.

What Does a Green Engine Light Mean?


Along with symbols, different manufacturers use colors to send you a message about your engine. Green is the standard color for when everything is on and working as it should. Green means go and it usually means that on your dash.

Sometimes you will get a blue light instead of a green one and the blue is saying the exact same thing or it is a reminder to buckle up, etc. These lights should not stress you out. For example, one green light mentioned earlier simply tells you the jake brake is on.

It is when the green light turns to yellow or red that you will have to begin to worry. Like a traffic light, a yellow is a warning that a problem is starting and needs to be checked. When the red light comes on, you know you need to stop as there is an issue that will get worse if you do not stop.

What Does a Jake Brake do?


The last word in the name gives you an indication of its function. It is a brake that helps larger rigs slow down. But what the name doesn’t tell you is that this brake is not on your wheels but in the engine and it uses the engine to help reduce your speed.

This braking system is designed to keep the truck's brakes from wearing out too quickly, especially when the rig is on a steep down grade. If you are wondering about the name, it comes from the company that invented this system, Jacob Vehicle Systems.

These systems are placed on heavy rigs as they have a lot of wheels and a lot of brake parts that can wear down quickly. When they do, a dangerous situation is created. jake brakes help avoid that dangerous situation.

How do Jake Brakes Work?


Another name for the jake brake would be the compression release brake and that is a better description of what the brake does. When enacted, the brake releases compressed air in the cylinder and then absorbs the power produced by the engine.

When the system was first invented, there was a switch you had to flip in order to activate the brake. Now all you have to do is lift your foot off the gas pedal and it automatically engages helping you slow your rig without damaging your wheel brake system.

When you are on a steep hill and you have lots of weight on your rig, this system helps make sure you do not have to look for and use a runaway lane. Those lanes were constructed for truckers and other heavy rig drivers to use when their brakes fail and the jake brake is not enough to slow the truck down.

Some Final Words

Green lights are not something you need to worry about. Instead, they are putting your fears to rest and telling you that all systems are a-okay and ready to go. It is when that color changes that you should investigate further and if there is a problem, call a mechanic to diagnosis the issue.

The different symbols you see on your dash are all there for communication and you should have your owner’s manual handy to let you know what the engine is trying to say to you.

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