Check Engine Light Diagnostics

What is the Check Engine Light?

check engine light image
The check engine light (also known as the CEL, Engine Light, Check Light, Malfunction Indicator Light or MIL) is an important warning system in your car. It lets you know there is something wrong with the engine management computer. The main purpose is to monitor your emissions system, but engines are so complicated it can have many different causes. When the light turns on, getting a Check Engine Light diagnostic is crucial.


What triggers the Check Engine Light?

There might be hundreds of failure codes that can trigger the check engine light. Yes, there are that many sensors on your car. They are all somehow related to how well your engine is running, and therefore can impact your vehicle emissions.


Is It Serious?

Yes and no.

Flashing Check Engine Light

If the light is blinking, it’s pretty serious and you should stop driving immediately. It might require pulling over as safely as you can and calling for a tow truck. It’s probably an engine misfire and you can do permanent damage, especially to your catalytic converter. That would be expensive.

Solid Check Engine Light

If it just stays on solid, the problem is less serious, but it should still be checked. Your car may seem to be running perfectly, but something went wrong to trigger it. If you keep driving around for a few days because you don’t have time to bring it to a repair shop, it’s probably not a big deal. But f you put a piece of black tape over the light or otherwise ignore it, you’re asking for trouble.


Free Check Engine Diagnostic?

Some shops advertise a “Free Check Engine Diagnostic”. Don’t fall for it. All you get for “free” is someone who will hook up an inexpensive code reader or code scanner and pull the code from your computer.

That is not a diagnostic, that is simply reading a code. There could be many causes that trigger a given code. The code will only point to the general area of the problem. It takes years of training and real-world experience to properly figure out the true cause.

Not only that, many important codes require a more sophisticated computer to read. This data is specific to a particular car and is licensed by each auto manufacturer.

A legitimate auto repair technician will charge you a fee for genuine diagnostic work. Because it takes time and experience. And an expensive computer. No $50-$100 scanner will do the job correctly.

But The Shop Says It’s Free!

If you go to one of these shops, they probably just “guess” what the problem is. You may hear them say something like this: “You need a tuneup, that will probably make the code go away.” So you spend however much on the tuneup and if it doesn’t fix the problem, they just say, “Well, you needed a tuneup anyway.”

And then they make another guess. If they guess right and fix the problem, you’re happy. Needless to say, they may need a few guesses. After you’ve spent a lot of money you finally say “No More!” and find yourself another mechanic.

If, by chance, the shop that gives you a “free” diagnostic has a well-trained tech that is actually able to figure out the real problem, they might fix it with cheap parts and charge you as if they were quality parts. Or they will add in other unnecessary repairs to pad the bill.

An honest and well trained technician will charge you a diagnostic fee and then let you decide if you want to proceed with the repair.

There is no such thing as a free lunch. Every shop has to earn money. Some do it honestly, others dishonestly.


Other Sources for a Free Check Engine Diagnostic

You can also get a free “diagnostic” at many auto parts stores. They hook up a scanner and pull the codes. They offer this service in the hope that you’ll buy the required parts to fix your car.

However, pulling the codes from your car’s computer is not a diagnostic. The code only give you a general idea of what may have caused the problem. Fixing your car based only a code is only a little better than random guessing. A proper diagnostic by an experienced tech is the only way to know for sure what the problem is and how to fix it.

Even if you like working on your own car, replacing parts based only a code can be very costly. If you replace one part and it doesn’t fix the problem, you’ll have to “guess” another part to replace. You can spend a lot of time reading online “experts” suggesting which parts are probably causing the fault. You might get lucky and fix the problem before replacing too many parts. Or maybe not.

Another approach people try to take is getting a free scan, and based on the code, they assume they know what the problem is. Then they bring it to a mechanic and tell them to replace only that part. After all, the computer told them exactly what was wrong.

What happens if that doesn’t fix the problem? You blame the mechanic, of course. But he only did what you told him to do. Don’t get mad at the mechanic, get mad at yourself for taking shortcuts in order to try and save money.


How Much Will It Cost for a Check Engine Light Diagnostic?

A check engine light diagnostic fee will usually cost around an hour’s worth of labor.

We won’t give you a free lunch, but here’s some free advice. The easiest “Check Engine” problems may be caused by either a gas cap not being on tight or oil level being low. You can probably check both of those things yourself, no need to bring your car in, and certainly no need to pay for that diagnosis.


Get Your Car Fixed Right. The First Time

Why Choose EBA

If you had another mechanic fix something and the problem didn’t go away, you’ve come to the right place. EBA will give you a full diagnosis of your Check Engine Light. Doing it correctly takes more than just plugging in a simple code reader. Even having the factory computer doesn’t solve all your problems. Once you get the specific factory code, there is still detective work that needs to be done.

Our technicians are ASE Certified and trained to correctly understand your automobile. We know how to figure out what’s wrong and how to fix it to keep you and your family safely on the road.

We don’t charge for work that you don’t need. It’s easy to increase our profits by replacing parts that don’t need fixing, but we’d rather keep you as a long-term customer. You can always trust us to tell you the truth. Sometimes there are items that need replacing down the road but are not absolutely necessary. We’ll show you what need fixing and we’ll always give you the options and tell you how long you can safely wait. You can also request to see the old part afterwards, so you’ll know we replaced something that really need to be replace.

We back our work with an industry leading 24 mth/24,000 mile warranty so you can rest assured that no matter what happens, you’re covered.

Trust the auto repair experts at EBA Automotive and give us a call if your car needs work.

This video explains the Check Engine Light


We’re just off Dillehay / FM2551 / Angel Pkwy, 1 mile north of Parker Rd and 1.3 miles south of Bethany/Lucas. Look for our sign at the roadside; yes, our sign is a Mini Van 🙂 Just south of Martin Stone Co, turn on to Curtis Rd. and you’ll see us in about 100 yards.

EBA Automotive Repair
5843 Curtis Rd #500
Allen, TX 75002
(972) 442-6400

Mon-Fri 7am-6pm

Happy Customers

“Excellent work, honest and dependable, and everyone goes that extra mile.”


Top Quality at Fair Prices - Don't Take Our Word For It

Read Our Reviews on These Websites

google reviews logo
facebook reviews logo
yelp review logo