Sidestep Free Check Engine Light Scans

This is my personal opinion on free check engine light services. At the bottom is a video from a local morning show with yet another opinion on the free diagnosis. There are a few companies offering no charge scans of your vehicle. The goal is to tell you why the engine light is on. In fact, recently more businesses have been jumping on the bandwagon to bring new customers into stores.

Misfire Codes are Important

Unfortunately, telling drivers what code is set in memory doesn’t really tell them exactly what’s wrong with the car. Also most of these businesses offering the free scan won’t  clear the codes to see if it’s an intermittent problem. This can be a logical first step in diagnosis.

If you’re in California or Hawaii they’ll say it’s against the law to clear them. In other States they might say it’s store policy not to erase codes.

This means you roll out the way you rolled in, with the light on. This can surprise people. Keep in mind, that some stores clear them anyway even if it’s against store policy. Ultimately the person holding the scanner has the power to make the final decision.

Auto Facts repair manuals
Auto Facts Repair Manuals

I don’t want to mention any brand names for obvious reasons. Still I’m sure you’ve seen and heard these companies advertising heavily on both television and radio.

Just a few examples are a popular automotive parts company and one of the largest franchise transmission services. You can probably guess who I’m talking about.

These companies would not be throwing down plenty of advertising dollars if this service didn’t create a generous amount of revenue or at-least a positive return on investment for their companies.

The free check engine light service may seem like a great deal at first. However, be aware it can lead to large auto repair bills if your not careful. The results are reliant on the experience of the employee holding the scan tool and how they present information retrieved to the consumer.

Check Engine Light Diagnosis is not Free

automotive diagnostic chartPulling codes is different from diagnosing the possible cause and the action needed to correct the issue permanently. In any case why not be prepared for the best and worst results. Let me give you a real world example of how this service can backfire.

I recently moved to secure a new job working for local government. I left 20 years of loyal patrons behind. A longtime customer had his check engine light pop on decided to track me down using social media. I recommended he purchase a cheap scanner so he could tell me what codes were set. This way the whole family could retrieve codes and clear the check engine light themselves in the future.

I explained to him how to find the diagnostic connector to the left of the steering column and plug in the scan tool. Then it’s just a matter of hitting the read button to retrieve the stored trouble codes. I advised him to write the code numbers down before using the erase button to clear them.

He agreed and visited a popular chain auto parts store to buy one of these DIY auto scanners. Here is what happened to my long-time customer. When he went to the local store and asked to see the different types of code readers available a young man behind the counter offered to scan the automobile for free.

o2 sensor and wire harness
o2 sensor and wire harness

The customer took the sales clerk up on the offer. He later told me he wished he had said no to this costly free service. The young man pulled a P0137 trouble code. This stands for an O2 sensor voltage low signal specifically for bank one sensor two from the cars computer memory.

The counterman said all you need to do is replace that sensor and reset the check engine light. My customer’s car was just out of the base warranty, as it had rolled slightly over 36,000 miles. He bought the oxygen sensor and a special tool to replace it. The grand total spent at the local parts store was $165.

He went home and replaced the oxygen sensor in his driveway. Then he made a deal to return to the parts store to have the code cleared. On the return trip back to his house the check engine lamp came back on.

He went back to the parts store and they pulled the same exact code for bank one sensor number two. To make a long story short, the Gentleman took his vehicle into the dealership. It had a bad catalytic converter. This was covered under the Federal emissions warranty.

Many people don’t realize that some major emissions components are cover past the base warranty. In this case, 8 years 80,000 miles. Repairs where done at no-charge. A refund was denied at the part store, because oxygen sensors and electronic components are not returnable items. This is to stop the try before you buy part changer.

Innova 3100 scan tool
Innova 3100 scan tool

Tools like the Innova 3100 on the left can be purchased for less than $100. This lets you read and erase codes yourself. If you reset the check engine light and it comes back on, You can take the car into a dealership or auto repair center armed with the first stage of real diagnosis.

Often the first step in a factory ladder diagram for obd-2 diagnosis will be to clear the codes and see if it returns indicating a hard failure. This will let the shop know you are an educated automotive consumer and two, you’ll have performed the first step in diagnosis, which is to retrieve and clear the codes.

This process can lower your auto repair bill. If you have some do-it-yourself skills you might be able to repair this fault on your own. A scan tool, coupled with the diagnostic chart for the set trouble code is very effective in solving even the most complicated problems.

A good automotive scan tool that can read data streams will cost around $110 with shipping. Add a user friendly online auto repair manual for your specific vehicle, this will cost $30. So for about $140 you could take a crack at an unlimited amount of check engine lights yourself.

Engine Light Service a Warning from Mom

My mother use to say, nothing in life is free. In my opinion this statement also applies to the free check engine light diagnostic services offered in a variety of locations.

Let’s be realistic, no company that I know of, will spend millions of dollars on advertising that doesn’t return something for their investments. The two major companies that I didn’t mention have different strategies at turning a free service into profits. Share this page with friends dealing with a check engine light.

The local parts company might pull the codes and then sell you those parts and the special tools required to replace them without any further diagnosis of the target system.

As in the above mentioned example, if you set an oxygen sensor code this doesn’t necessarily mean you need to replace an oxygen sensor. The set trouble code means you should confirm any failed components by further diagnosis of that particular system. In my opinion the best way to go is by following a factory repair manual tree chart to find out what the problem is.

The service Company that offers the free check engine light scan might pull your code and then prepare an estimate to solve your car problems. In some cases, this estimate has been padded to include the diagnosis that they said was free.

Next up is another opinion on the subject. My favorite part of this video is towards the end. The news anchor tells the mechanic what happened to her when she went in for diagnosis of her service engine soon lamp. The story caused so much pain for the mechanic he had to cover his ears.

Free check engine light help video

This link takes you back to the auto homepage where you can learn more about me and this automotive website.