Code Reader vs. Scan Tool

Pick the device that is best for your needs

Mechanics testing a car
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There aren’t any hard and fast rules as to what constitutes a basic car code reader and what qualifies as a scan tool (like Fixd), but there are a few things that set these devices apart. Both devices feature basic code reading and clearing functionality, but that’s often where a code reader’s feature set ends. Scan tools, on the other hand, may include advanced data reading and playback features, extensive knowledge bases, diagnostic procedures, and even built-in testing equipment.

Code Readers vs. Scan Tools

As to whether you need a code reader or a scan tool, neither device is necessarily better than the other. Code readers are cheap and easy to use. If all you need to do is read and clear codes, then an inexpensive code reader is a great tool to have.

Some affordable code readers even provide basic access to the full range of parameter IDs (PIDs) that your car’s onboard computer provides, and that can be powerful information if you know what to do with it.

A lot of parts stores and shops will check and clear your codes for free, so folks who would do fine with a bargain-basement code reader could be better off looking into that sort of service

However, a good scan tool is always going to be a much more useful tool in the right hands. Scan tools are more expensive, but they do everything a code reader can do and a lot more. You might also want to consider going with a low-cost option like an ELM327 scan tool if you already have a compatible device that you can use with it.

Code Reader Features

No two code readers are exactly alike, and feature sets can differ from one model to another. In general, there are some things every code reader can do, other functions that you should be on the lookout for, and a lot of stuff that no inexpensive code reader can handle.

Things a code reader can do:

  • Read and display codes
  • Clear codes and reset the check engine light

Things a code reader may be able to do:

  • Display trouble code names
  • Read and display live data
  • Display freeze frame data
  • Display readiness monitor status
  • Reset readiness monitors

Things a basic code reader can't do:

  • Provide troubleshooting information or tips
  • Record and play back live data
  • Graph data or graph specific PIDs
  • Read manufacturer or pending codes
  • Utilize functions that require bidirectional communication

Scan Tool Features

Different scan tools provide a wildly varying set of features depending on whether you’re dealing with consumer- or professional-grade equipment. Like code readers, scan tools allow you to read and clear codes.

However, even low-end, consumer-grade scan tools include information such as code definitions and some basic troubleshooting tips. High-end scan tools include much more in-depth diagnostic and troubleshooting procedures, and some of them have built-in testing equipment like scopes and multimeters.

Limitations of Basic Code Readers

If you buy a code reader and feel like it isn’t doing what you need it to do, then you probably ended up with a bare-bones device that is nothing more than the dictionary definition of a code reader. If you need to read anything but generic, hard-set codes, or do anything other than read and clear codes, then a basic code reader isn’t going to do the trick. However, a midrange device that can read and display PIDs and freeze-frame data may fit your needs just fine.

ELM327 Dongles

Another option that may be worth exploring is a type of scan tool that functions as an interface between your car’s onboard computer and another device, like a smartphone, tablet, or laptop. These are typically referred to as ELM327 scan tools, but they can function as anything from a basic code reader to an advanced scan tool and the core of a DIY infotainment system depending on the software you use.

Do You Need a Car Code Reader or Code Scan Tool?

Professional automotive technicians typically require high-quality scan tools to work efficiently, while the average do-it-yourselfer should be able to get by with a basic code reader or nothing at all.

If you prefer to work on your own car, then the type of scanner or reader to get is a function of how much money you want to spend and how much money or time that purchase can save you.

Spending a lot of money on a decent consumer-grade scan tool certainly makes sense if you own a small fleet of vehicles, while others should be able to get by with the free code reading service offered by a local parts store and an internet search to find out what their trouble codes mean.