OBD2 Scanners – What is Mode 3?

Automotive scan tools use 10 different modes to perform all of their needed functions. These modes help the tools perform highly complex operations that keep our vehicles running strong. Mode 3, possibly the most important mode, however, is quite simple. Mode 3 is what a tool uses to display the stored codes, letting you know what error codes your vehicle has produced.

Automotive Scan Tools Mode 3

Mode 3 lists the 5-digit codes that are stored in your vehicle when an engine error occurs. These codes correlate with a specific error, pointing a knowledgable mechanic (or someone with the right information) towards a potential fix for the car or truck.

Basic code readers will simply give you the 5-digit code, like P0400. Others scan tools may give you the coded definition, telling you that P0400 is the code for an “exhaust gas recirculation flow malfunction.” More advanced (and expensive) scan tools will give you all that information as well as possible fixes. The potential fixes come from mechanics who work with the tool manufacturers. When the mechanic fixes a problem on a car, he or she sends the information to the tool maker, and that information is logged into the tool’s database.

Advanced scan tools can also do more than just display engine codes. Many tools can display error code information related to the body, antilock brake system, heating and A/C system, and airbag. These give even more functionality to the already useful scan tools, and they can help you avoid costly diagnostic fees. None of the information, however, would be available without the use of Mode 3.

Get the Information You Need with Mode 3

Mode 3 is the backbone of an automotive scan tools. All readers and advanced units will be able to use Mode 3 to display vital engine information. Whether you have an advanced tool or an affordable yet handy code reader, both will utilize Mode 3 in order to give you the information you need.

Summary of all OBD2 Scanner Modes