Free Check Engine Light Diagnosis?

There are so many different ads out there announcing different prices for and even FREE check engine light (or service engine soon light) diagnostics that most people are confused. Why the differences, and if it can be done for free, why pay for it? And just how important is it to bring your car to a shop when that check engine light comes on?

First, it is important to understand that the check engine light performs a valuable service. It should not be ignored. It is telling you that something is out of sync within your car’s emissions system that needs to be addressed. That is why if your check engine light is on when you need to have your smog certificate renewed, it will be an automatic failure.

It is also important to understand that the service to diagnose the cause of your check engine light can only be performed correctly if the shop has invested in the right equipment, the right software and trained technicians with access to the right information. Equipment and software must be updated frequently, and is done at a great expense to the shop owner. The technicians must go through training, approximately 40 hours per year, in order to have the up to date knowledge needed to interpret information accumulated by the diagnostic equipment. This information is available at an ongoing expense paid by the shop to manufacturers, on-call services, and after market online services. The only information provided by the vehicle’s control unit is an error code with a definition, and this error code only points to a vehicle’s particular system. The technician then must determine what component or components within the system have malfunctioned. Repair can only take place after this step is accomplished. Anyone without the knowledge and equipment is just guessing at the correct repair. The danger of this guesswork is the risk of additional damage occurring to other vehicle components because the cause of the warning light was not repaired correctly.

So make sure that the facility you take your vehicle to for this type of repair has the ability to do it correctly. If the first step in the process (determining why the light came on) is not being charged for, or if it is a minimal charge, it is a red flag that there has been no investment in the correct equipment, software or training. The outcome of any subsequent repair may not be what you expect. You may also find that after the code is pulled you will be asked to spend more money to dig deeper into why the code was triggered. Even worse is when the code is pulled, a diagnosis is given to you, but the diagnosis is wrong because of a lack of knowledge and correct equipment. It may seem as though you are saving money by responding to an ad for an inexpensive check engine light repair, but you can end up with more problems than you had in the first place. “Free” is attractive, but not always the “free” you had in mind.