In order to determine why your Check Engine Light is on, a mechanic will connect a handheld device to the OBD II connector under your dash (in a vehicle made in 1996 and onward). This lets the mechanic access the trouble code stored in the computer and begin diagnosing the problem. However, there are many different devices that do similar things, and it helps to know the differences between them.
Code reader vs code scanner
You’ll find two primary categories of devices out there – code readers and scan tools. There’s a lot of blurring of the lines between these two options, but here are the main differences:
Code Reader: A code reader is generally the cheaper of the two options, and also the most limited in terms of functionality. They basically connect to the OBD II connection, and tell you what the code is. You can then choose to clear the code if you want. That’s where their features usually end.
Scan Tool: A scan tool is generally manufactured for use in an automotive shop, and provides a robust set of tools for testing, diagnostics and more. Mechanics can also access more than just the ECU – the code scanner generally provides access to codes and problems in the ABS system, traction control and other supplemental systems.
In addition to the difference in functionality, there’s also a considerable difference in price. A code reader can cost hundreds but a good scan tool might set you back thousands, depending on the software and tools included. Some of these are very high-end, with touchscreen capabilities and additional equipment that can be used to make a more accurate diagnosis, test components on the car, and even control the vehicle’s onboard software to simulate different operating conditions.