If the check engine light is flashing on your GMC, you need to pull over immediately and turn off your car, especially if accompanied by oil or temperature warning lights.

A flashing check engine light spells trouble. If you continue to drive you’ll risk serious – and expensive — damage to your engine.

However, a flashing light is different than a check engine light that is simply illuminated. Not every check engine warning light signals a parade of big bills. Sometimes the problem is as simple as tightening the fuel cap.

Every responsible driver should understand the meaning of their car’s warning lights. The GMC owner’s manual will help explain these symbols and show where they’ll appear on the dash. The lesson here is don’t ignore any warning light that comes on.

And no, placing a piece of black electrical tape over the light will not make the issue go away. For more information, see our article What Happens When I Get a Check Engine Warning?

There are many reasons why the check engine light might come on in your GMC, but not all of them are serious. For example, one of the more common reasons for the light to come on is a faulty gas cap. It might need replacing or it could simply be loose.

Sometimes a check engine light will come on when nothing is really wrong with your car. A change in humidity or other temporary changes in the environment could trigger the light. If that’s the case, the light will go off by itself after a relatively short period of driving time.

However, an illuminated check engine light could also be a huge red flag being waved right in front of your face warning you of a more serious problem. Are you releasing excess pollutants? Are you consuming too much fuel? You just never know. (By the way, if your check engine light is flashing on your GMC, pull over immediately and turn off the car. A flashing light spells trouble.)

In short, if your check engine light comes on, you have two options:

1. You can diagnose the problem yourself by buying an OBD II scanner and check the engine codes.
2. If you’re not the DIY type, and most drivers aren’t, take your car to a mechanic and let the experts do their job.

That’s the million-dollar question. If your check engine light comes on and stays on, there are two things you can do:

1. Diagnose the problem yourself by buying an OBD II scanner and checking the engine codes.
2. Take your car to a certified professional for a proper diagnosis.

Some drivers feel confident working on their own cars. If so, option #1 may work. But for the majority of drivers, we recommend taking the car to a professional GMC mechanic. The issue could be anything from a loose gas cap to something more serious, like a misfiring engine. You just never know.

Here’s something else to consider: Are other warning lights coming on as well, like temperature or oil pressure? If so, then you’re dealing with a major problem and your car needs service without delay.

One more thing, and we can’t stress this enough — if the check engine light is flashing on your GMC, pull over immediately and stop your car. Not kidding. There’s something majorly wrong and you don’t want to risk further damage by driving it.

In the end, if your check engine light comes on, it’s best to heed the age-old advice…it’s better to be safe than sorry.

A dealer usually charges a service fee to check your check engine light. But if you’ve built a good relationship with a favorite GMC dealership over the years, it never hurts to ask.

Another approach would be to locate an independent auto mechanic who might diagnose your problem for free. Doing a little leg work and making some calls could save you money.

Nowadays, many auto part stores will diagnose your check engine light without charging a fee. All it takes is to walk into the store and ask someone behind the counter. Or, again, ring them up and ask.

If you can’t find a free option and are curious what it might cost, the national average across all vehicles for a check engine light diagnostics service is about $131 to $209.

If resetting the check engine light on your GMC is your main concern, we’ll assume you fixed the problem that caused it to come on in the first place. That said, if the light is still illuminated after making the necessary repairs, your car’s computer simply needs a little nudge to tell it things are all good.

A few different ways to reset your check engine light are:

• Let it go off by itself
• Turn your ignition on and off several times in a row
• Disconnect your battery and reconnect it
• Buy an OBD II scanner (they’re relatively inexpensive) and follow the instructions (it’s pretty easy)

One of these four methods should do the trick. But let’s say the check engine light on your GMC never goes off. Or it does but comes back a few days later. This means you still have a problem, and it could be major.

At this point we recommend you make an appointment with a professional mechanic and have him or her diagnosis the cause.