Modern cars are technical marvels that use multiple complex computer systems and modules that run everything from your engine to your back up camera. Due to computer advancements and YouTube repair videos, many customers erroneously believe that computers automatically diagnose the vehicle. We simply hook up a scanner to figure out what is wrong. The faulty part is then changed and the computers are cleared. It is rarely this simple due to the all the complex computers and modules that run your modern car.
Check engine lights are triggered by a component in your car that is out of tolerance which turns on the service light on your dashboard and gets stored in the automobile’s computer. Generic scanners can interpret codes as follows, “P0300” which can help point to the general system where a component is failing. Most people tend think that modern auto repair simply requires a code scanner to tell you what parts to change then you simply change the part and your car will be fixed. If this were true then independent or specialty mechanic shops would have gone out of business long ago.
Let’s look at the common generic code P0300- Multiple Cylinder Misfire. This check engine fault can be triggered when something is wrong with the car’s ignition system. Having that information in mind, what do you change? The spark plugs, ignition wires, or coils? Let’s say you change change everything which costs you hundreds of dollars, but the check engine light keeps coming back? That can happen because fault code P0300 can also be caused by a bad crank sensor, inadequate fuel pressure, or a bad wire anywhere along the ignition system. Nine out of ten times having a code read in an auto parts store parking lot will not tell you what repair needs to be performed.
An experienced technician in a fully equipped shop will be able to get the fault codes and use knowledge and experience to start methodically troubleshooting the problem. This might require checking voltages, continuity, fuel pressure, or many other things which require specialized equipment, knowledge, and time. That is why diagnostics from reputable shops take time and have a cost.