When that dreaded little check engine light illuminates on your dashboard, you may find yourself sighing expecting the worst. It always seems to come on at the wrong time, and you really have no way of knowing right off the bat what it means.

This light could mean any level of things. It could be a big problem, or it could be something very small, and unfortunately, there aren’t two lights to let you know which is which. Should you find yourself in this situation, there are a couple things you can do immediately to see if you can solve the problem yourself.

The first and easiest thing you can try is simply tightening the gas cap. Sometimes the check engine light can be set off just from something this small, and if this is the case, you got a lucky break. If that doesn’t work, you may have a bigger problem on your hands, in which case the most important thing you can do is to go get your car checked at your local mechanic. Even if you are fearful, it might be notifying you of a larger, more expensive issue. Ignoring this light could make things worse and eventually cost even more money later on, or leave you stranded in a sticky situation.

If the light is still illuminated after checking your gas cap, you’ll want to make sure there aren’t any other lights showing up on your dashboard which could alert you to something else like overheating or low oil. In these situations, it is safest to pull off the road, shut off the car completely, and address the situation with a mechanic as soon as possible. It may also be that your check engine light is either blinking or staying illuminated. If the light is not flashing, the problem may not be quite so serious, but if the light is blinking, this could indicate a more serious immediate problem, and again the safest thing to do is pull over.

Since the light can mean any number of things and doesn’t provide any clarification, your best bet at this point is to head to your local auto mechanic and ask them to run a diagnostic on the car which will help find the root of the problem. This is a little computer that the mechanic will plug in under the dashboard, and it provides a code of what the issue is. This is your best bet if you can’t tell the issue immediately because it will let you know exactly what the problem is so you can address it sooner than later.

Of course, if your car is smoking or is stalling you would need to get to a repair shop immediately to be safe, but regardless, it’s best to have your car checked by a professional to avoid any further damage or costly repairs. Addressing this dreaded little light sooner than later really can save you a lot of problems further down the road.