One question we get asked a lot here at Marks Auto Service is, “Do you really need to do a diagnostic test?” When it comes to vehicle repairs, the diagnostic test actually saves you time and money, which is why we do it. Gone are the days of popping the hood and isolating an automobile’s issue visually. Cars, trucks, and SUVs are giant computers now, and the engine diagnostic test helps us help you.
Your vehicle has an onboard computer that monitors all operating systems at all times. You might think this is a relatively new thing, but Ford first introduced onboard computers in 1969 when it designed a computer-controlled anti-skid system. What started as anti-skid has become every single system in your car, truck, or SUV, and systems that aren’t operated by computers are, at the very least, monitored by them. So, yes, your vehicle is a giant computer.
You might ask why and the answer is simple: Safety. When it comes to monitoring the systems in your automobile, the computer has one goal in mind and that is to ensure everything is operating as it should be. The computer can detect an issue long before you can – long before we can in some cases. If a system does return an error, no matter how slight, the computer will illuminate a dashboard warning light, which is your signal to pull over and stop.
In addition to monitoring your vehicle while it’s in operation, your onboard computer also checks all systems when you first fire up the ignition. This is why you see your dashboard warning lights all on at the same time for a few seconds. Your onboard computer is scanning everything to make sure all is well. Once they all turn off, you know your vehicle is road-ready, and you can head out to work, school, on your errand or wherever life is taking you.
So, Why the Test?
If a dashboard warning light or your check engine light comes on, the computer processes an error code that we mechanics understand. When we run the diagnostic check on your vehicle, we see a full report of the code(s) and know exactly what is wrong and how we should repair it. If your vehicle doesn’t illuminate a warning light, the diagnostic check still guides us to potential problems that might not be visible to the naked eye. It tests all systems and then provides a full report on their health.