Should You Buy a Bidirectional Scan Tool and Other FAQ

Reviewed by

Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on October 23rd, 2023

Reading Time: 4 minutes
Summary
  • Bidirectional scan tools are used to read the diagnostic data in your vehicle’s computer. They can also be used to input data into your vehicle’s computer.
  • There are a lot of advantages that come with using bidirectional scan tools. For example, they help you read OBD codes, they perform numerous functions, and they’re convenient and easy to read.
  • You can buy a good-quality bidirectional scan tool for around $350-$900.

Taking your vehicle to the mechanic costs time and money, and while it’s your responsibility as the owner to always make sure your vehicle is in top shape, it isn’t always easy to make time or shell out money every time an issue pops up on your vehicle. This is where bidirectional scan tools come in.

Modern vehicles run on a standard on-board diagnostics (OBD) computer system that sends out error codes whenever it finds a malfunctioning part in your vehicle. With a bidirectional scan tool of your own, you can read these error codes before deciding to visit a mechanic.

While a code reader can also read and clear codes and give you generic engine data, a bidirectional scan tool can do so much more.

What Is a Bidirectional Scan Tool?

Also known as a coding scanner or engine scanner, a bidirectional OBD2 scanner is a small handheld device that connects to your vehicle’s OBD port.

Just like a regular OBD2 scanner, a bidirectional scan tool can read the diagnostic data in your vehicle’s computer. Just plug it into your vehicle’s Diagnostic Link Connector (DLC) port, and let your scanner read the DTCs logged in your vehicle’s computer system.

What makes a bidirectional scan tool different from a regular OBD2 scanner is its ability to input information into your vehicle’s computer. Think of it as a 2-in-1 tool that not only reads and interprets data from your vehicle, but also inputs commands to test your vehicle’s brakes, transmission, and other systems.

A bidirectional scan tool (a.k.a. coding scanner or engine scanner) can not only read and interpret data from your vehicle, it can also input commands to test your vehicle’s brakes, transmission, and other systems.

What Are the Advantages of Owning a Bidirectional Scan Tool?

A bidirectional scan tool can be pricey, but is it worth it in the long run? Find out yourself by considering these advantages:

Reads OBD Codes

Diagnosing issues in your vehicle can be intimidating, especially if you’re doing it all on your own. With a bidirectional scan tool, however, you’ll have a helping hand that can narrow down which part or system is causing problems for your vehicle.

Keep in mind that just because you have a code stating a specific system is having a problem doesn’t mean that it’s actually the issue at hand. Still, a bidirectional scan tool is a great way to narrow down the suspects until you get to the actual culprit causing problems for your vehicle.

Perform Different Functions

As a step up from your regular OBD2 scanner, the bidirectional scan tool can run a variety of tests on your vehicle’s systems. Its functions can vary depending on the brand, but some scanners can reset the oil light, perform bidirectional active tests, and even calibrate the steering angle sensor.

Some can also perform electronic parking brake service functions and test your vehicle’s battery and charging system.

Great Readability

Having to learn how to use new tools can be difficult, but you don’t have to worry about that with bidirectional scanners. Bidirectional scan tools are typically equipped with the latest technology, including a display that can show you information in easy-to-understand charts and graphs.

Some scan tools can even send data to your laptop with the help of some software.

Convenient Technological Features

The market for bidirectional scan tools has gotten competitive over the years, with many manufacturers adding more features to improve user experience. Some scan tools even allow for wireless connections to certain vehicles through Bluetooth VCI.

Saves Time and Money

Time is money, and a trip to the mechanic can cost you both. Having a bidirectional scan tool can save you an unnecessary trip to the mechanic by diagnosing the problem for you. In some cases, you might even be able to reset certain systems using your scan tool. 

You can also save yourself some time by using your scan tool to immediately find the source of the problem instead of spending hours manually testing each of your vehicle’s systems.

Other Bidirectional Scan Tool FAQ

Do You Need to Keep Your Car On While Scanning?

This depends on the type of scan tool you own. Some OBD2 scanners come with built-in batteries, while some will need power from your vehicle to operate. If your bidirectional scan tool is one of the latter, you may have to turn your vehicle on (without turning the engine on) while using the scanner. If you aren’t sure, you can always check your scanner’s manual.

How Much Does a Bidirectional Scan Tool Cost?

The price of a bidirectional scan tool can vary depending on several factors, such as its brand, features, and type. You can purchase basic OBD2 scanners for under $60. However, advanced OBD2 scanners will most likely cost over $200, with quality bidirectional scan tools selling for around $350 to $900.

About The Authors
Reviewed By Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Tony Harlin is a Master Gas and Diesel Diagnostic Technician with over 18 years of experience. He works full-time at a large independent automotive shop as a driveability and repair technician working on all types of vehicles with a focus on diesels. ASE certifications include A1-A9, L1 and L2, as well as X1.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and Anthony Harlin, ASE Certified Master Automobile Technician