Our car experts choose every product we feature. We may earn money from the links on this page.
Did your vehicle's Check Engine light just pop on? An OBD-II scanner can point you in the right direction—and potentially save you a bundle. Medical PCB Board
Seeing your vehicle's check-engine light come on can throw a wrench in your travel plans. It can also feel a little scary: Does it mean your ride is headed for the scrapyard? Or is there a simple fix? Without an expensive trip to a repair shop, there's really only one way to find out: an OBD-II scanner.
In 1996, OBD (On-Board Diagnostics)-II became mandatory for all cars sold in the United States. OBD-II uses a port that allows communication with a vehicle's onboard computers, providing critical insight to mechanics and technicians on the internal workings of the vehicle. This is how the pros determine what's wrong with your car when that check-engine light mysteriously lights up.
These days, consumers can easily access this information, potentially saving hundreds of dollars on trips to the mechanic. Instead of paying a tech to plug an OBD-II scanner into your car and tell you what's wrong with it, you can take a look at the codes first—if you have the right OBD-II scanner.
But which one should you buy? There are huge price differences between OBD-II scanners, which can cost from less than $20 up into the thousands. As with most gadgets, the more you pay the more features you'll get. To help you decide which one is right for you, we selected a variety of OBD-II scanners at various price points and ran them through the Gear Team testing garage.
For this test, we omitted any wildly expensive scanners, as those are geared toward professional repair technicians. Instead, we focused on consumer OBD-II scanners meant for garage warriors like us, who just want to know what the error codes are—and what to do next.
OBD-II scanners vary greatly in price, ranging from tens of dollars to thousands. During our testing, we came up with two unofficial categories: display and diagnostic OBD-II scanners.
Display OBD-II scanners simply show error codes. If you just want to read what the code is and see some limited vehicle data, these are the scanners to get. You'll have to do some research on your own to figure out what that code means—and to determine your next steps. Display scanners are cheaper and less complicated to use, but they may lack many of the handy functions that diagnostic scanners provide.
Diagnostic OBD-II scanners are serious auto repair tools, boasting far more diagnostic information than display scanners. They cost more as well. These are for DIYers who feel comfortable disassembling vehicular components and putting them back together. Diagnostic scanners offer advanced component and module testing, allowing deeper investigation into that pesky Check Engine light. Some even offer technical advice, common repairs, and Technical Service Bulletins (TSBs). If you find yourself wrenching on cars more than the usual garage gremlin, consider investing in one of these.
Vehicles equipped with OBD-II typically have a port under the dashboard on the driver's side. They can be tricky to find, but they're always accessible. Some cars have them on the left side of the steering column; others will locate the port on the right side. To access the information in the port, simply plug the scanner in and turn the key on, without the vehicle running. You can start the engine, but there is a risk that whatever the reason for the Check Engine light, it could damage components.
A vehicle's error codes show as a five-digit Diagnostic Trouble Code (DTC). This code will display alongside a short description that may or may not make any sense to you, akin to someone simply saying their hand hurts when in reality their pinky finger is broken. The DTC will point you in the right direction, but it's up to you to investigate and unearth the real issue. A number of DTCs, typically those related to the powertrain, are common across all vehicles and can be read by any scanner. However, some DTCs, such as those for braking or chassis systems, can be automaker-specific, and you may need to investigate which scanners (if any) will communicate with your car's various onboard computers. Some even are capable of doing nearly everything a dealer can do, including some programming.
We also tested both corded and Bluetooth OBD-II scanners. Overall, we felt the interface and user experience were more accessible through Bluetooth scanners and their associated apps, but they did take longer to set up. With an app on your smartphone, further info is already in the palm of your hand. Meanwhile, the speed and simplicity of corded scanners were definite advantages. Which one is better? That comes down to user preference.
We wanted to use a common vehicle for this test to best evaluate compatibility, so we pulled in a 2005 Toyota Corolla owned by Gear Team tester Collin Morgan and set to work. The old beater had just rolled over 250,000 miles, so we were excited (and slightly nervous) to see what the scan tools would uncover.
Knowing that there are different OBD-II scanners for different situations, we avoided pitting them all against one another. Instead, we decided which scanner works best for each situation and rated them on that metric. We took detailed notes on the capabilities of each and started our testing.
To manufacture a check-engine light, we unplugged the mass-airflow sensor on our Toyota Corolla, started up the car, and verified that the light was on. Then we simply plugged each scanner in and evaluated the following parameters:
Comparing our notes from this test helped us choose which OBD-II scanner is best for various applications and which scanners don't quite live up to expectations. Here are our top picks for the best OBD-II scanners.
Shop the best OBD-II scanner deals on Amazon
The Ancel BD310 is our choice as the Best Display OBD-II Scanner for Home Use. We loved the scanner's happy medium between corded and Bluetooth capabilities and felt the app's interface was excellent.
It's a unique scanner, as you can use it with just the corded interface or connect it via Bluetooth and use the free app to access more data, diagnostic resources, and performance testing.
The BD310 was quick to connect and display codes, and it provided many of the perks of expensive scanners while staying affordable.
For an OBD-II scanner with a wider range of diagnostic capabilities, we were impressed by the testing functions, bidirectional control, and additional diagnostic suggestions of the Innova 5610. No other scanner in our test offered this many features.
It's a hefty scanner with a price to match. But with that price comes a plethora of functions inaccessible by other, cheaper OBD-II scanners. We were able to access five system and actuator tests, a hybrid/EV battery test function, an ABS bleeding procedure, and much more.
So while the price is steep, it's worth the investment if you work on cars more than the average person.
There are definitely perks to Bluetooth OBD-II scanners, and the BlueDriver Bluetooth Pro is our pick for the best. Featuring an intuitive, easy-to-use app and some helpful diagnostic direction, we applaud this tiny little scanner.
It took a bit longer to set up the BlueDriver initially, but once we were in, it was a gold mine. The tile-style interface was exceptionally easy to use, and we had no issues finding codes, tests, and other data.
Features accessible through the app include model-specific features, TSBs, a battery reset procedure, and more, along with the expected DTCs. Another benefit to the Bluetooth scanner is the consistent updates, meaning the info is always current.
For those just looking for a no-frills code reader, the Motopower MP69033 is a great choice. It simply reads and displays codes quickly, with a neat graphing function for certain live data PIDs—all while not breaking the bank.
We liked the separate up and down buttons, which is a nice perk compared to the interfaces of other budget OBD-II scanners. The screen is old-school and pixelated, but it didn't bother us.
The MP69033 read our codes quicker than all of our hardwired scanners, displaying them in just over 17 seconds. A neat graphing function is also available for Car Speed, Coolant Temp, Load Value, and Engine RPM. It's not incredibly useful, but more of a neat little added touch.
We gave the Innova 1000 an Honorable Mention for its inclusion of diagnostic resources such as recalls, TSBs, and predicted repairs.
It just falls short of the BlueDriver in a few areas. The Innova provided less information and data, is more expensive, and the app is less intuitive than our winner's. All that said, it worked just fine and it's a solid OBD-II scanner for most consumers.
The Foxwell NT301 struck us as a middle-of-the-road entry in our OBD-II scanner test. The screen is crisp and easily navigable, but it seemed a bit high-cost to justify a Best Of award.
Along with the screen and UI, some tests were available to run, including an EVAP leak test and O2 monitor tests. There's also a print function via Micro-USB that could come in handy. But the price point didn't seem right for the functionality.
The Autel AL319 OBD-II scanner was slow to boot up, slow to read codes, and difficult to navigate. Thanks to a single directional button, churning through the menus takes some practice (and patience). We recommend you look elsewhere for a simple code-reading scanner.
The Fixd Bluetooth Scanner lays excellent groundwork; it's just behind a paywall. While we could read and clear codes with just the base scanner, everything else requires a subscription to access. While there are some cool features once you pay (I/M readiness monitors, tips from mechanics, repair cost calculator), other OBD-II scanners provide access to similar functions without the monthly subscription.
Don't let the cheap price fool you—it reflects the quality of the Akface Bluetooth OBD-II scanner. The Akface doesn't use its own app, but rather piggybacks onto a selection of third-party apps. This makes connectivity a bear, and once you're in, you get simple code-reading capabilities and nothing else. Yes, it's cheap, but the Akface is not worth the hassle.
To test OBD-II scanners, we pulled a 2005 Toyota Corolla into the Car and Driver garage. We then set to work manufacturing a check-engine light (CEL) by unplugging the mass-air-flow sensor. Once the CEL was verified, we plugged in each OBD-II scanner and ran them through our testing parameters.
The corded scanners were simple plug-and-play, but the Bluetooth scanners required a bit more time to set up. This included installing the app, connecting the scanner to our iPhone 11, and setting up accounts.
We took detailed notes during our testing about the parameters we established. Overall, we found the corded scanners were quicker to use, while the Bluetooth scanners were more accessible and user-friendly once setup was complete.
For each scanner, we ran through a list of testing parameters:
An On-Board Diagnostics version two (OBD-II) port is a standardized diagnostic interface included in nearly all vehicles made in or after 1996, which is when the OBD-II specification was made mandatory for all cars sold in the United States.
OBD-II ports communicate with the vehicle's on-board computer system to retrieve data, including engine speed, fuel consumption, cylinder performance, intake air temperature, and much more. Included in this data can be fault codes, known as DTCs, which are set by the vehicle's computer system when a fault is detected with a particular component.
DTC stands for Diagnostic Trouble Code. It is a code generated by a vehicle's on-board diagnostic (OBD) system when it detects a malfunction or problem within a specific system or subsystem of a vehicle. DTCs are standardized across various makes and models of vehicles, and while all vehicles produced must support a specific subset of these codes if they use an OBD-II port, manufacturers also have additional codes, including some that may be specific to their vehicles.
Each DTC fault code is made up of five characters: A single letter followed by four numbers. The letter denotes which of the four main systems the fault has been detected in:
The second character is a number that specifies whether it's a generic OBD-II code or a manufacturer code. (Manufacturers reserve the right to generate their own codes if there isn't a generic code for a specific problem they'd like drivers/techs to be able to diagnose.)
The third character is either a letter or number that specifies which of the vehicle systems is throwing a fault:
The fourth and fifth numbers denote the specific fault being detected. It can be any number between zero and 99.
Nearly all modern OBD-II scanners will summarize what the error code is alongside the five-character alphanumeric code. For some of the more advanced models, there's even a code look-up function that will further explain what the fault code is referring to and what might be causing it.
In the case of the Bluetooth OBD-II scanners, some of the apps will also include video explainers pulled from YouTube that will show you how to further diagnose and even repair the faulty components responsible for the code.
Although the exact location of the OBD-II port can vary from vehicle to vehicle, the port is typically located around the footwell on the driver's side, beneath the steering wheel and above the pedals.
This test was conducted in an environment that provided equal testing procedures for each product: the Car and Driver garage. We tested each OBD-II scanner equally to compare them based on time to display code, cord length, user interface, and more. Upon tallying our findings, we agreed that our test provided enough information to recommend picks to our readers.
Hearst Autos combines the talent, resources, and expertise of three of the largest, most influential automotive publications in the world. We don't need to game SEO algorithms for traffic, or promote lousy products to make a sale. We're far more concerned with our legacy, our reputation, and the trust that our readers have in Autoweek, Car and Driver, and Road & Track to deliver honest evaluations and expert opinions.
Read more about our product testing and evaluation process here.
Collin Morgan is an Associate Commerce Editor at Hearst Autos, where the former Rust Belt mechanic and gadget enthusiast presents the best gear for your automotive endeavors.
Katherine Keeler is an Assistant Testing Editor at Hearst Autos. By day she evaluates tools for your enjoyment; by night, she Frankenstein’s her ever changing fleet of rust-bucket-oddities back to repair. Her dream is to open a roadside attraction where the public can view, drive, and learn repairs at her emporium of curious cars.
Gannon Burgett loves cameras, cars, and coffee: a perfect combination for his Hearst Autos work. His byline has appeared in USA Today, Gizmodo, TechCrunch, Digital Trends, the Detroit Free Press, and more.
Best Tools to Fix Dents, Dings and Bangs
The Best Tailgating Essentials of 2023
The Best Truck Tires, According to Experts
Essential Gear for Overlanding Adventures
45 Cool Car Accessories – Car and Driver
Tested: The Best Booster Car Seats
Labor Day Tools Sales 2023: Lowe’s, Home Depot
Top-Rated Seat Covers for Your New Ford Bronco
The Best Motorcycle Jackets You Can Buy
Best Car Battery Chargers for 2023, Tested
Best Foam Cannons for 2023, Tested
A Part of Hearst Digital Media
We may earn a commission for purchases made through our links.
Industrial Motor Drive Control Board ©2023 Hearst Autos, Inc. All Rights Reserved.