Rows of cars in traffic at dusk.


After a long day at work, you’re driving home during a slow commute, thinking about all the things you need to do before it’s time to sleep. Suddenly, a dashboard light catches your eye, taking you away from your thoughts and bringing you back to the moment at hand. It’s the dreaded check engine light!

How long has that been on?

And more importantly, what does it mean?

In today’s blog, we want to go over what a check engine light might mean, as well as provide pointers on what you need to do when this light comes on.

Why Is This Light On?

Some people think it’s a fluke, and they figure the light will turn off on its own once the “glitch” resolves itself. This is just wishful thinking, though! That light will not turn off on its own. It’s on because some type of engine maintenance is needed, or some part of the vehicle’s system has malfunctioned. Ignoring it is not a good idea!

Your car’s onboard diagnostics system has detected some kind of issue, and it’s telling you through that little dashboard light. The issue could be small, but it needs to be taken care of nonetheless. The longer you wait, the costlier the fix might be. If the light happens to be flashing, you’re right in figuring that there’s a certain sense of urgency involved with the problem that’s been detected.

What’s Wrong With My Engine?

So, what exactly is wrong with the engine when that check engine light is on? The problem could be one of many different possibilities. Here are some of the systems that might be affected:

  • Emissions: Some part of the emissions control system may be malfunctioning, and your car may be spewing too much pollution.
  • Fuel: This system includes the fuel tank, pump, filter, carburetor, and injectors, and a flaw in any of these parts can reduce your gas mileage at best, or leave you stranded in one of several possible worst-case scenarios.
  • Ignition: If it’s an ignition system issue, the problem could lie with the spark plugs, ignition coils, or other components. Signs pointing to a possible ignition issue include a rough idle, slow acceleration, or difficulty starting the car.
  • Exhaust: Several different things could be going on when your car’s exhaust system is involved, including an exhaust leak that’s letting too much oxygen in, or a clogged exhaust system that brings down your fuel economy.

Of course, these are just some of the possibilities of what’s gone wrong. There are many others, and your trusted auto mechanic will be able to shed more light on the situation, make recommendations, and take care of any needed auto repairs.

Call to action for finding a reliable car mechanic.

Do I Need To Pull Over Right Away?

That’s a good question, and it’s hard to answer this definitively. If the check engine is on continuously (without flashing), it’s generally safe to continue driving to your destination and make an appointment with a reputable auto repair shop as soon as possible. If you notice that your car is not responding, that the engine “feels” especially sluggish or uncooperative, or if you hear that it’s misfiring or making unusual sounds, you’re probably better off pulling over and calling for roadside assistance.

In the event that your check engine light IS flashing, then yes, you need to pull over. A flashing check engine light indicates a more major problem; continuing to drive when your engine or the components that connect to it are compromised can lead to bigger, costlier problems if you don’t pull over and get your car towed to your favorite auto repair shop.

Next we’ll go over a few specific, common scenarios that explain why your check engine light may be on. Remember, however, that many other possibilities exist. When in doubt, have your auto mechanic take a look to determine what, exactly, is going on.

Possible Cause 1: A Bad Catalytic Converter

A catalytic converter is necessary for the engine’s combustion process; it helps protect our lungs and the environment! The catalytic converter breaks down toxic gases and converts them into safer elements. A problem with this system can point to a number of possible failures, including worn piston rings, leaking exhaust valves, or an intake manifold leak, among other culprits.

Possible Cause 2: A Sensor Needs Replacing

Your engine is a sophisticated design. It checks itself at key locations via important sensors. When one of these sensors goes out, your diagnostics can’t work properly. The fix is to have your auto mechanic replace the affected sensor. Possible broken sensors that would trigger the check engine light include the fuel system’s oxygen sensor, or the mass airflow (MAF) sensor.

Possible Cause 3: The Fuel Cap Is Loose

This is a simple problem to fix, but until that fuel cap is replaced correctly, your engine will experience problems. You will lose fuel via evaporation if the cap is broken, missing, or even loose, and your whole exhaust system can become unbalanced.

Possible Cause 4: There’s A Faulty Vacuum Hose

There are different hoses in your engine and throughout your vehicle, each one playing an important role. If one of these hoses is faulty, problems will arise. A hose may become disconnected, or it may crack or develop a tear. Depending on which hose is at fault, you’ll experience different symptoms.

Take Your Vehicle To An Auto Repair Shop

When your check light engine goes one, don’t panic, but don’t ignore the light, either. It’s trying to tell you that something needs attention. The longer you ignore it, the more extensive and costlier the repairs may be. You may even find yourself stranded with an engine that’s called it quits because supporting systems weren’t maintained properly. Don’t let too much time elapse when that indicator goes on; get your car to an auto repair shop at your earliest convenience (and sooner than that if the light is flashing).

Schedule An Appointment With Metric Motors

We at Metric Motors have been helping motorists in and around Loveland, CO for more than 40 years. Our experience with different makes and models poises us to diagnose problems quickly and make auto repairs reliably.

A check engine light could lead to challenges with starting your car, poor fuel mileage, a rough-running engine, or other issues that we’re sure you don’t want to experience. Don’t stress out over that light on your dashboard. Bring your car in to Metric Motors of Loveland, and we’ll take care of the problem as quickly and economically as possible. We’re also here for any other vehicle maintenance or repair services you may need. Reach out to us today to schedule an appointment!