Are you gripped with dread, fear, and horror at even the thought of your check engine light coming on? How do you feel when it actually does come on? I know that I am immediately thrown into panic and my brain says something like “well, I guess your car is broken forever now.” Not helpful, brain!!! But then I did a little research on why my check engine light comes on, and apparently, it’s not usually nearly as bad as you might think it would be. In fact, the most common reason can often be solved by just tightening your gas cap. Check out why your check engine light might be coming on in our list below.

1. It could be your gas cap. Seriously, if your gas cap is loose or broken or cracked or totally missing, this could be what’s making that light come on. So if the light appears, the first thing you should do is check on your gas cap. It’s a possibility that you’ve found the solution. If the cap is broken or missing, your dealer can replace it.

2. Spark plugs are also a likely culprit. Everyone needs to get them replaced every so often (usually about 100,000 miles in newer cars) and it might be time for yours to be switched out.

3. Your Mass Airflow Sensor could be to blame. This part tells your car’s computer to add the right amount of fuel based on the amount of air that’s coming in to the engine. When this piece is broken, your emissions increase, your efficiency decreases, and your car might stall.

4. Maybe your oxygen sensor(s) are to blame. Your O2 sensors monitor the unburned oxygen in your exhaust, which tells your vehicle’s computer how much fuel is being burned in your engine. When the sensor is broken, your mileage can decrease. Don’t wait too long to get this checked out.

5. It could also be your catalytic converter. This is also a reason your check engine light might be coming on. If this part is broken or faulty, it won’t reduce your exhaust gases like it’s supposed to, which in turn will decrease your MPGs and mess with your acceleration. Get this fixed IMMEDIATELY, even though it is the most expensive repair on the list. (Note: if you need to get your O2 sensors replaced but don’t do it, you can burn your cat out.)