How Car Diagnostic Software and Tools Work

February 17, 2012

Most car diagnostic software is based on reading data from your vehicle's OBD-II (onboard diagnostic) system. Learn how to use a car diagnostic tool.

Using Car Diagnosic Software

Car diagnostic software helps keep your vehicle running smoothly. This software is built into all cars made after 1996, and it is included in many earlier cars as well. The latest technology is called OBD-II, which stands for on board diagnostic system. The OBD-II is incredibly useful to mechanics and other people curious about the status of their vehicle when something seems to go wrong.

Positioning of the Software
The OBD-II system in your vehicle has sensors and ports in various parts of the car. There is one underneath the dash of most cars, and many vehicles also have a port under to the driver's seat. There are other sensors and activation centers spread throughout the vehicle in order to monitor the activity of various parts of the car. Essentially, the software is located all throughout the vehicle.

Function of the Software
The OBD-II monitors the proper functioning of your vehicle. It not only controls certain engine functions through the on board computer, it also keeps a record of all of the things that happen to your car as you drive it, good and bad. This information can be used later by mechanics, who download a series of diagnostic codes from the OBD-II port. These codes explain what is going on with the vehicle, and are the basis for the diagnosis of your problem and how to fix it when the check engine light comes on or if you experience other problems.

The software that measures the diagnostics of your car takes regular readings of different systems in the car. This is primarily centered on the engine, but the OBD-II includes sensors for the chassis, frame and other parts of the car too. At each reading, the software records a particular acronym or code that represents the functionality of that system. This information is stored within the OBD-II system and can be retrieved by attaching a computer to the port. The mechanic then downloads the codes and translates them to determine exactly what was going on at each point of inspection. This helps to calculate when and how damage occurred to a part of your car.

How to Use a Car Diagnostic Tool

An auto scan tool can be used to read the diagnostic software. Also called a car code reader or an OBD-II scanner, this tool is a useful way to determine the issues with your car without having to take it in to a dealership or a mechanic for an expensive analysis.

You'll need the following materials in order to take a diagnostic reading of your car:

Install the Computer Software
Computer scanner systems require that you connect the scanner to a computer. An iPhone or iPod Touch will also work with devices such as the REV iPhone Car Diagnostic Tool. In order to get a reading from the car diagnostic device, install the software that comes with the scanner system. This allows the computer to display the readings from the diagnostic tool.

Connect the Scanner
Find the port where you can attach the scanner. This port is often located on the dash, typically just below the steering wheel and to one side or another. Look for a small indentation and a simple port system. The port connector may also be underneath the driver's side of the front seat. If you're having a hard time figuring out where to connect your scanner, check the owner's manual for your car or consult with a professional.

Get a Reading
Follow the instructions from the scanner tool and the software on your computer to take a reading of the car diagnostic device. This will help you to determine exactly what the problem is by sending a series of codes to your computer, which will be displayed.

Translate the Codes
Using the guidelines from the code translation sheet, figure out the problem that has caused the malfunction or the check engine light to come on. You can then decide the best way to remedy the problem or take your car to a mechanic.