What to do if the check engine light in your semi-truck turns on

You’ve just left the truck depot with a fresh load of cargo. The fuel is topped off, the tires are rotated, and you just changed the oil. As you turn onto the interstate and start climbing a hill, you notice a new indicator on the dashboard. You take a deep breath, look down and see what you were hoping to avoid –– the check engine light.

Learning your semi needs maintenance can be stressful, especially if you’re on a long-haul trek and nowhere near home base. Even so, check engine lights are a part of trucking life.

Below are some tips on understanding the check engine light and what to do to keep yourself and your cargo safe.

What is the check engine light?

The check engine light is a safety indicator that first came into use during the 1980s. Basically, it’s a quick and convenient way for your truck to tell you that something’s amiss under the hood. The check engine light is part of your truck’s onboard diagnostic (OBD) system. The OBD is like the brain of your semi and contains dozens of electronic sensors. These sensors monitor everything from the oxygen flowing through your engine to the amount of fuel being burnt.

When the OBD detects an error, it attempts to make repairs on its own. If those self-repairs fail, it alerts you by flipping on a dashboard indicator.

Do I need to stop driving if my check engine light comes on?

If your check engine light turns on, you don’t need to panic. A simple check engine light is just the initial warning that something may need attention. It can mean something is a little out of whack and the engine will try to resolve it, it could mean a minor issue needs repair in the future, or it could mean a very big repair is needed soon.

So it is important to find out what the code means right away so you know if something needs attention immediately or if you can finish your trip first. To find the codes there are various ways of getting that information these days that range from plugging into the truck directly or being able to pull the codes online through certain mechanic portals your company has set up. Checking with your company or a dealership service center can get you pointed in the right direction to find the issue.

What causes the check engine light to come on?

With today’s technology, there are one thousand and one reasons it could be triggered. However, some common reasons include:

• A loose gas cap
• Low fluids
• Excess oxygen in the engine
• Dead spark plugs
• Faulty or damaged hoses

If you’re unable to troubleshoot the cause on your own, pull over and wait for a tow truck or a professional mechanic. It’s better to determine the underlying cause and repair it than it is to take a risk and potentially damage your vehicle.

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