Today’s vehicles are run by multiple computers or control modules. To give you an idea of what I am talking about, the engine is managed by an electronic control module or ECM. These control modules monitor and control the fuel, emissions, temperature, the timing of the engine, braking, starting, charging, transmission shifting and speed. The electrical accessory systems that add luxuries like power windows, door locks, seats, mirrors, heating, and air conditioning, are also run by a control module, called a body control module or BCM.

How Do You Know If Your Car Needs A Diagnostic?

When one of these systems in your vehicle starts malfunctioning, a driver is alerted by either the illumination of a warning light on your dash. The vehicle could also start malfunctioning by not starting, causing a rough idle, running poorly or a loss of power, or the fuel economy level could have changed, or possibly another symptom. In order to properly diagnose what is going on with the vehicle and conclude what the proper repair would be, it takes knowledge, diagnostic equipment, and time for the automotive technician to run the needed tests. Unfortunately, when you tap into the vehicle’s ECM it does not tell you what is wrong. In fact, the ECM makes adjustments and changes to compensate for the symptom that it is seeing, so the vehicle will still operate as close to normal as possible. The diagnostic process starts with retrieving the code or codes from the ECM. These codes give you the circuit or circuits that are affected, and that the condition that the vehicle’s computer is seeing. From there a qualified diagnostic technician follows a diagnostic path of pinpoint testing to find the source of the problem and what is causing the condition.

Medical Diagnostics vs. Automotive Repair Diagnostics

As a comparison, a medical doctor has to run tests on patients that are having symptoms to find what is causing a health symptom or condition. The initial exam and tests have a charge associated with them, whether they are blood tests, biopsies, x-rays or scans. In much the same way, an automotive repair shop also has charges associated with the expertise, time, and labor of a technician who performs these tests and forms a conclusion based on the information gathered from these tests. To be honest, this diagnostic process can be the most complicated part of vehicle repair. The technician who is delegated this task is a specialist in vehicle computer diagnostics. These technicians are constantly furthering their education and training and upgrading their tools and equipment—since the systems on vehicles are constantly evolving and changing.

Save Time And Money With A Vehicle Diagnostic At All About Automotive

So, don’t be surprised when you are quoted a diagnostic fee next time your vehicle acts up or a warning light comes on in your dash. In reality, it is less expensive to pay for a proper diagnosis than it is to replace car parts based on what might be failing or what is most commonly replaced or the hunch factor.

Steve and Karen Johnston are owners of All About Automotive, providing quality auto repair services and preventive maintenance for your vehicle in Historic Downtown Gresham. If you have questions or comments, call them at 503-465-2926 or email them at [email protected].


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