Check Engine Light Diagnostic Cost

Check Engine Light Diagnostic Cost (A Helpful Guide)

You must have heard this advice over a million times: If your car check engine light comes on, you should take it in for a diagnostic test. But do you need to pay anything for this diagnostic test or is it a free service? How much should you pay for a CEL diagnostic test?

Check engine light diagnostic test will cost you between $60 and $100 in most auto repair shops, depending on the region. We advise you to compare the fees for at least three places before committing to ensure you get the best deal.

Discover more details about the CEL diagnostic cost for your car, whether the cost is worth it, whether you can do the test on your own and save money, and other related helpful information.

How much does a check engine light diagnostic costs?

The average cost of a check engine light diagnostic test is between $60 to $100 in most auto repair shops. However, this price can vary depending on your region and you might even find some shops offering the services at a much higher fee of up to $400.

Keep in mind that this cost doesn’t include taxes as well as other fees the service center may charge you for the diagnostic test. The price can also go higher depending on your car model labor charges.

(This list by Forbes shows the average check engine light diagnostic cost by state).

Basically, what happens during this diagnostic test is that the auto mechanic plugs a code reader into your car computer and pulls out the codes to help them tell you where the problem is.

How much does a check engine light diagnostic costs

And based on the results of this diagnostic test, the auto mechanic may suggest repairing the engine or any other fixes to fix the light. This will definitely cost you extra, depending on the complexity and severity of the issue.

How much you pay for repairs will depend on the type of issue that triggered the check engine light. Some of these issues are minor and don’t require costly repairs. Examples include a loose gas cap, a bad gas cap, misfiring spark plugs, etc.

Some repairs are quite expensive and will cost you thousands of bucks to fix. You should pray these issues never get to your car.

These Car MD Vehicle Health Index stats lists the most expensive repairs such as transmission replacement, battery failure, cylinder head assembly, hybrid inverter assembly, fuel injection pump, mass flow sensor, and catalytic converter replacement, to name but a few.

Just like any other financial decision, we advise you to compare at least three places before you commit. This will ensure you get a good deal and receive value for money. Some shops will waive the diagnostic fees if you have the repairs done by them.

PRO TIP: Carefully go through the mechanic’s service agreement before penning down your signature for a car diagnostic test to ensure you understand every part of it. Some auto repair shops will lure you with free diagnostic tests only to camouflage hidden fees into the service agreement’s granular details.

Why are car diagnostics so expensive?

The auto repair shops charge high for diagnostics for a number of reasons. To start with, they use more expensive equipment that costs up to $3000. This is more than a typical OBD II scanner used by auto parts shop.

Secondly, they invest in extra training for their technicians so that they’re able to carry out these tests and find out what issues your car engine is going through.

Thirdly, carrying a full diagnostic on your car takes time and the labor cost takes the biggest proportion in the test fee.

While it takes a few minutes for an auto parts shop to pull out codes for your car, an auto mechanic may take up to an hour or hours to pull codes from your car computer. And they don’t stop there.

Why are car diagnostics so expensive

They then go ahead and test the procedures for the components relating to the fault code they obtained.

Most car owners convince themselves that auto shops charge a lot for diagnostics because they believe they just plug into your car computer and read the codes. But this isn’t true. They do more than just get the codes.

They do a FULL diagnosis of your car, including hands-on tests and analysis, which is time-consuming. But it is also the best way to find out the problem causing the CEL to come on and offer the best repair possible.

When you keep all the above in mind, you’ll agree with us that the diagnostic fee makes sense and is well worth it (find out more about why the diagnostic test is worth it below).

Read:  Check Engine Light Flashes 3 or 4 Times Then Goes Off (Explained)

Is a car diagnostic test worth it?

Absolutely! A car diagnostic test is totally worth it! It helps you detect the problems your car engine is experiencing early enough before they cause a breakdown.

The cost of the test is also on the lower side and quite worth it since it usually covers the equipment cost as well as the time it takes the technician to pull out the fault codes from your car computer.

Using the diagnostic tools, the mechanics can get to your car computer for stored information and manufacturer notifications about your car history.

Is a car diagnostic test worth it

This gives them a complete picture of your car and enables them to give you the best repair services possible, fixing the underlying issues for good.

Here are the key benefits of a car diagnostic test that makes it valuable:

  • Car diagnostic test saves you money: The test helps you detect a fault before it grows into something more catastrophic, helping save you money in the long run.
  • The diagnostic test saves lives: By catching faults before they become catastrophic, this test can also help save your life and that of your loved ones. For instance, can tell you when you need to replace the brakes before they fail on the freeway and cause accidents.
  • Repairing your car engine issues gets easier: Check engine light diagnostic test helps the mechanic narrow down on what issue is affecting your car. The auto repair shop will access the vehicle computer system for stored data and manufacturer notifications. They’ll then use this data to easily find out what issue your car is experiencing and fix it the right way.
Check Engine Light Diagnostic Cost

When you think of ignoring the check engine light and assuming you know what caused it to come on, always remember it popped on for a reason.

And that reason can develop into a more serious, costly issue if you continue to ignore it. So, always take in your car for CEL diagnosis and your car will always be in top condition.

Can you carry out check engine light diagnostic cost on your own?

If you find the diagnostic cost too much, you can carry out the test on your own. There are many OBD II scanning tools available at all price ranges. Some are basic while others are more advanced and you can easily get one for your budget.

While doing your own diagnostic tests on your car may work, it’s not always recommended because you may never get to the bottom of the problem—just like when you go for a free diagnostic test at your local auto parts shop.

Can you carry out check engine light diagnostic cost on your own

Taking your car to a reputable auto mechanic shop for diagnosis is the best bet. This is because these professionals usually have more enhanced computers that cost up to $3000.

These are more advanced than your $100 model or the one at the part store and are capable of carrying out a more in-depth analysis of the car.

Moreover, these mechanics have loads of experience with cars before. They will not only be relying on the scanning tools but will also do hands-on tests and analyses which further help with your car diagnostic and pinpointing the problem causing the CEL to come on.

Where can I get a free diagnostic test on my car?

Yes, most local auto parts shops will do the diagnostic test on your car for free. Some auto repair shops may also offer free check engine light diagnostic services.

However, keep in mind that free can be expensive at times! Some of the shop owners will try using the free diagnostic test to convince you that the underlying issue is catastrophic. This is a trick they use to inflate the cost and make you spend more.

That said, we recommend you only work with reputable establishments to avoid getting ripped off. Before you work with a new auto repair shop, be sure to go through reviews to see whether they’re professional or another unscrupulous auto repair shop.

Where can I get a free diagnostic test on my car

If you’ve got your doubts about a diagnosis carried by an auto repair shop, don’t hesitate to get a second opinion from another shop. The more information you have, the harder it becomes for you to be manipulated.

As you get your car diagnosed, remember that not all tests are a scam. Provided you work with a reputable shop and they recommend expensive repairs or parts replacement, you may have no other option but to spend the extra money to keep your car in top condition.

Read:  Check Engine Light After Rain: Why It Comes On (And What To Do About It)

How long does it take to do a check engine light diagnostic?

How long it takes to do a check engine light diagnostic will depend on what issue your car has. However, the average time you should expect to spend at the repair shop is about one and a half hours.

In case your car is suffering a more complicated issue, you may need to hang around at your mechanic’s for a little longer, up to 2 or 3 hours. This is because more complex issues may require the technician to remove a few parts of your car for easier access and further diagnosis.

After identifying the issues causing the check engine light to come, the mechanic may suggest repairs which could be replacing parts, cleaning dirty areas, etc.

How long does it take to do a check engine light diagnostic

Afterward, they may repeat the diagnostic test after the repairs to ensure the initial error has been fixed. This only adds more hours to the diagnostic test.

An easier way to avoid spending all those hours at the mechanic is having your car codes read at an auto parts shop or doing the reading on your own.

However, we don’t recommend this path as it isn’t a full diagnosis and doesn’t always help identify the problem your car has.

Going to the mechanic is still the best bet as they’ll do a more in-depth analysis and pinpoint the problem causing the CEL to pop on.

If you own a vehicle, chances are you’ve encountered the dreaded check engine light at some point. It’s important to understand the meaning behind this warning light, as it can indicate a wide range of issues with your vehicle. Our articles on what to do when your check engine light comes on and off and what a flashing key on position means can provide you with the information you need to address these issues. The article on what to do when your check engine light comes on and off explains the reasons behind the intermittent warning light and what you should do when it appears. Meanwhile, our article on what a flashing key on position means describes what this warning light indicates and how to deal with it. Check out our articles to stay informed and ensure your vehicle is running smoothly.


1. Is an engine diagnostic free?

yes, an engine diagnostic can be free, depending on who is doing it for you. Most local auto parts shops will do it for you for free. if you own an OBD2 scanning tool, you also won’t need to pay anything. However, auto repair shops offer the service at a fee and we encourage you to have them do a diagnostic for you because they carry out a full diagnosis until they find the problem, unlike the parts store that just gives you the error codes and nothing more.

2. Does AutoZone diagnose check engine light for free?

Yes, AutoZone diagnoses check engine light for free. If your check engine light comes on and you don’t know the reason, go to the nearest AutoZone and they’ll pull the error codes stored in your car computer memory for free. However, they may not be able to pinpoint with 100% accuracy the cause for the CEL to come on, so you may just want to visit an auto mechanic for a more in-depth analysis of the underlying issue.

3. How urgent is the check engine light diagnostic test?

It depends on the CEL itself. If the check engine light is flashing, then this is an urgent matter and needs immediate action. Take your car in as soon as possible for diagnosis. If the engine light is steady and your car is running fine, the issue isn’t that urge. However, you should still book an appointment with your mechanic as early as possible to avoid incurring costly repairs in the future.

Final Verdict

The average cost for a check engine light diagnostic test falls between $60 and $100 in most auto repair shops. This cost covers only labor costs and doesn’t include fees and taxes, and doesn’t factor in your specific car model or your location.

After the auto mechanic conducts the diagnostic test, they may suggest repairs that will cost you more money. The repair cost can be anything from a hundred bucks to several thousand bucks depending on how severe and complete the engine issue your car has.

Remember, a car diagnostic test is totally worth it as it helps you catch an error early enough before it turns into a more serious issue, helping you save money and even lives. 

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