The modern car is a complex machine, but thankfully, diagnosing issues doesn’t have to be shrouded in mystery. OBD-II scanners have become indispensable tools for car owners and mechanics alike, offering a direct line into your vehicle’s onboard computer. Whether you’re facing a perplexing dashboard light or simply want to understand your car’s health better, an OBD-II scanner can provide the insights you need without the immediate expense of a professional diagnosis.
Navigating the world of OBD-II scanners can be daunting, especially for newcomers. The market is filled with options, each promising to be the best. Having spent years testing and evaluating a wide array of OBD-II scanners, we’re here to guide you through the selection process. We’ve rigorously tested scanners across different price points and feature sets to identify those that truly stand out.
While OBD-II is the standard for modern vehicles, some enthusiasts and owners of older cars might also be interested in OBD-I capabilities. While this review primarily focuses on OBD-II scanners – the current industry standard – we’ll also touch upon the relevance of OBD-I and scanners that cater to both systems where applicable.
Below, you’ll find our top recommendations for the best OBD-II scanners available today, suitable for everyone from the casual car owner to seasoned professionals. We’ll delve into what makes each scanner exceptional, along with a guide to understanding how OBD-II scanners function and deciphering those often cryptic error codes.
For those seeking a wireless and highly portable option, the Topdon TopScan stands out with its user-friendly Bluetooth connectivity and comprehensive diagnostic features. If budget is a primary concern, the Launch CR529, priced around $40, delivers remarkable value and essential functionalities. For professionals or those demanding advanced diagnostic capabilities, the Topdon Phoenix Lite 2 offers a near-professional diagnostic experience, albeit at a higher price point of $799.
Here’s a quick overview of our top OBD-II scanner picks for the current market:
Top OBD-II Scanner Picks: Quick List
These are the best OBD-II scanners you can purchase right now, based on our extensive hands-on testing. Continue scrolling for detailed reviews of each product and insights into their standout features.
1. Topdon TopScan: Best Mobile OBD-II Scanner
The Topdon TopScan distinguishes itself as the easiest Bluetooth scanner to set up, based on our rigorous testing. Despite its compact form, it packs a suite of professional-grade features, including comprehensive diagnostics, repair guidance, parts information, and even predictive analysis to anticipate potential issues.
Dive Deeper into Topdon TopScan
2. Launch CR529: Best Budget-Friendly OBD-II Scanner
The Launch CR529 combines compact size with robust performance, delivering all the essential OBD-II scanner functionalities you’d expect, alongside some advanced features typically found in more expensive models. Its lifetime support and updates further enhance its value, making it an unbeatable option for the price.
Explore the Value of Launch CR529
3. Topdon Phoenix Lite 2: Best Professional-Grade OBD-II Scanner
Resembling a rugged handheld console, the Topdon Phoenix Lite 2 is designed to withstand demanding environments while offering professional-level diagnostic capabilities. It’s equally suited for professional mechanics and car enthusiasts who require a powerful and durable scanner.
Discover Professional Diagnostics with Topdon Phoenix Lite 2
4. Ancel BD310: Best Dual-Purpose OBD-II Scanner
The Ancel BD310 is not only an effective OBD-II scanner but also functions as an auxiliary dashboard display, providing real-time engine specifications. Its sleek design, smartphone compatibility, and affordable price make it a versatile choice.
Learn More About the Ancel BD310’s Dual Functionality
5. Carly OBD-II Scanner: Best OBD-II Scanner with Companion App
The Carly OBD-II Scanner’s value is highly dependent on your car’s make, with brands like VW, BMW, and Ford benefiting most from its features. However, its standout feature is its exceptional companion app, offering extensive customization and professional-level diagnostic tests.
Explore the Carly OBD-II Scanner and App Integration
In-Depth OBD-II Scanner Reviews: Top Picks
Why Trust Tom’s Guide? Our team of expert reviewers dedicates countless hours to evaluating products and services to bring you unbiased and comprehensive recommendations. Learn more about our rigorous testing and review process.
1. Topdon TopScan: Best Mobile OBD-II Scanner
(Image credit: Topdon)
Overview:
Topdon TopScan: The Ultimate Tool for Unlocking Your Car’s Potential
Read our Expert Review
Key Specifications:
- Display: None (App-based)
- Connectivity: Bluetooth
- Handheld: No
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Keys: None (App-controlled)
- Warranty: 2 years
- Dimensions: 3.2 x 2.0 x 1.1 inches
- Weight: 2.6 ounces
Pros:
- Exceptional diagnostic coverage for a wide range of vehicle systems.
- Real-time live data monitoring for in-depth analysis.
- Unique performance indicators, including horsepower and torque estimation.
- Comprehensive maintenance item coverage.
Cons:
- The Bluetooth transmitter module is somewhat bulky.
- Advanced features may require a subscription after the first year.
The Topdon TopScan might appear unassuming at first glance, but this compact scanner is packed with features that belie its size. More than just a basic Bluetooth OBD-II adapter, the TopScan significantly exceeds the capabilities of many competitors in its class. Its ease of Bluetooth setup is remarkable, making it incredibly user-friendly.
Beyond standard fault code reading and I/M Readiness tests, the TopScan excels in performance and efficiency diagnostics. It can even estimate your vehicle’s horsepower and torque – features rarely found in scanners at this price point, or even in some much more expensive models. Whether you’re aiming to optimize your car’s performance or ensure its roadworthiness, the TopScan is an invaluable addition to any toolkit.
Read our full Topdon TopScan review
2. Launch CR529: Best Cheap OBD-II Scanner
(Image credit: Future)
Overview:
Launch CR529: Unbeatable Value in an OBD-II Scanner
Read our Expert Review
Key Specifications:
- Display: 2.8-inch Color Screen
- Connectivity: Handheld (Cable)
- Handheld: Yes
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Keys: 8 Physical Buttons
- Warranty: 1 Year
- Dimensions: 6.5 x 3.8 x 1.2 inches
- Weight: 11 ounces
Pros:
- Exceptionally affordable price.
- Lifetime free updates.
- Convenient pre-inspection report generation.
Cons:
- Does not support manufacturer-specific specialty codes.
- Feels somewhat heavy for its size.
- Limited 1-year warranty.
The Launch CR529 redefines value in the OBD-II scanner market. Its sub-$50 price tag is just the beginning; the level of diagnostic features it offers is truly remarkable for the cost. We were particularly impressed by the extensive capabilities packed into such an affordable device.
While compromises are expected at this price point, such as the absence of manufacturer-specific codes and a slightly hefty feel, the CR529 still delivers essential features like live data, instant inspection readiness checks, and surprisingly detailed insights into your car’s systems. The inclusion of lifetime updates is a significant advantage, ensuring long-term usability without subscription fees.
While the CR529 might not satisfy the demands of professional mechanics, it’s an excellent choice for car owners seeking a reliable and budget-friendly diagnostic tool for their personal use.
Read our full Launch CR529 review
3. Topdon Phoenix Lite 2: Best Pro-Level OBD-II Scanner
(Image credit: Future)
Overview:
Topdon Phoenix Lite 2: Bridging the Gap Between DIY and Professional Diagnostics
Read our Expert Review
Key Specifications:
- Display: 8-inch Color Touchscreen
- Connectivity: Bluetooth & Wi-Fi
- Handheld: Yes (Tablet-style)
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Keys: Touchscreen Interface
- Warranty: 2 Years
- Dimensions: 10.2 x 7.2 x 1.7 inches
- Weight: 2.6 pounds
Pros:
- Professional-grade OBD scanner features.
- Versatile handheld design with Wi-Fi and Bluetooth.
- Large, user-friendly 8-inch touchscreen.
- Extensive array of diagnostic tests and live data parameters.
- Includes adapters and a protective hard case.
Cons:
- Bulky and heavy, potentially cumbersome in tight spaces.
- High price point.
- Subscription required for updates after two years.
The Topdon Phoenix Lite 2 occupies the higher end of the OBD-II scanner spectrum, justifying its premium price with a wealth of features and capabilities that cater to both serious DIY enthusiasts and professional mechanics. While it’s more expensive than many other capable scanners, the value it delivers is substantial.
A standout feature is its wireless operation, with a Bluetooth receiver connecting to the OBD port and communicating with the tablet-style control pad. This wireless freedom enhances mobility around the vehicle during diagnostics. Despite its size and weight, the Phoenix Lite 2 is designed for workshop environments with a rugged build and a convenient kickstand.
Beyond basic fault reading, it offers advanced features like live data graphing and in-depth fault information, rivaling professional-grade tools. However, be aware of the post-warranty update subscription cost, which adds to the long-term expense.
Read our full Topdon Phoenix Lite 2 review
4. Ancel BD310: Best Dual-Purpose OBD-II Scanner
(Image credit: Tom’s Guide)
Overview:
Ancel BD310: An OBD-II Scanner That Does Double Duty
Read our Expert Review
Key Specifications:
- Display: 2-inch Color Screen
- Connectivity: Bluetooth & Handheld (Cable)
- Handheld: Yes
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Keys: 4 Physical Buttons
- Warranty: 3 Years
- Dimensions: 5.1 x 2.4 x 0.6 inches
- Weight: 5.4 ounces
Pros:
- Lightweight and compact design.
- Functions as both a scanner and a secondary car display.
- Offers both handheld and Bluetooth scanning capabilities.
Cons:
- Minimalist interface may be less intuitive for some users.
- Small 2-inch screen.
The Ancel BD310 distinguishes itself with its dual functionality, serving as both a traditional handheld OBD-II scanner and a Bluetooth-connected device that can display real-time engine data on your smartphone. It can also function as a secondary dashboard display, showing key engine parameters directly in the car.
Its compact and lightweight design makes it exceptionally portable and easy to store in a glovebox. While the 2-inch screen is small and the four-button interface is somewhat basic, these design choices contribute to its portability without significantly hindering its diagnostic capabilities.
The 56-inch cable provides ample reach, and the BD310 supports essential functions like I/M readiness tests and displays performance data such as coolant temperature, engine timing, and RPM.
Read our full Ancel BD310 review.
5. Carly OBD-II Scanner: Best Companion App Integration
(Image credit: Carly)
Overview:
Carly OBD-II Scanner: Unlocking Car-Specific Features Through a Powerful App
Read our Expert Review
Key Specifications:
- Display: None (App-based)
- Connectivity: Bluetooth
- Handheld: No
- I/M Readiness Test: No
- Live Data Display: Yes
- Keys: None (App-controlled)
- Warranty: Lifetime
- Dimensions: 2.9 x 1.5 x 0.7 inches
- Weight: 0.7 ounces
Pros:
- User-friendly and feature-rich companion app.
- Extensive customization options within the app.
- Real-time live data display through the app.
- Covers maintenance and repair information within the app.
- Lifetime warranty and updates.
Cons:
- Feature availability varies significantly by car make and model.
- App subscription required for advanced features can be costly.
The Carly OBD Scanner stands out primarily due to its exceptional companion app. While many Bluetooth scanners offer basic app interfaces, Carly’s app is among the most sophisticated and user-friendly we’ve tested.
The app not only diagnoses issues and clears fault codes but also provides repair assistance and tools to assess used cars for potential problems. The lifetime warranty is a rare and valuable benefit.
However, the functionality of the Carly scanner is heavily dependent on your car’s make and model. Certain features are more comprehensively supported for brands like VW, BMW, and Ford. Additionally, accessing advanced features beyond basic OBD-II functions requires an ongoing app subscription, which can add to the overall cost.
Read our full Carly OBD scanner review
Other OBD-II Scanners We’ve Tested
- Innova CarScan Mobile 1000 (★★★★☆)
The Innova CarScan Mobile 1000 is a highly innovative Bluetooth OBD-II scanner, inheriting Innova’s renowned features, including predictive diagnostics, in a completely wireless, phone-based format. Its exceptionally simple setup process makes it a compelling Bluetooth-only option.
Read the full Innova CarScan Mobile 1000 review
- ThinkCar ThinkDiag TKD01 (★★★★☆)
While larger than typical Bluetooth OBD-II adapters, the ThinkCar ThinkDiag TKD01 boasts a robust, almost indestructible build. It offers extensive manufacturer-specific error codes and advanced fault code analysis that can resolve minor issues without professional mechanic intervention. A subscription is required after the first year.
Read our full ThinkCar ThinkDiag TKD01 review.
- Autel AutoLink AL539 (★★★☆☆)
The Autel AutoLink AL539 is specifically designed for diagnosing electrical issues, featuring a built-in multimeter. It excels at identifying problems like damaged wiring, short circuits, and blown fuses. It also provides a wide range of live data and pre-inspection readiness checks.
Read our full Autel AutoLink AL539 review
Frequently Asked Questions About OBD-II Scanners
What exactly is an OBD-II Scanner?
Mechanics rely on OBD-II scanners to efficiently diagnose car problems, rather than manually disassembling and inspecting every component. These scanners connect to your car’s OBD port to access data from the onboard computer system.
At their most basic, OBD-II scanners read and interpret error codes generated by your car when it detects an issue. More advanced scanners offer real-time system monitoring and can even predict potential future problems.
What is the OBD-II Port?
The On-Board Diagnostics Version Two (OBD-II) port is a standardized interface found in almost all passenger vehicles sold in the US since 1996, Canada since 1998, the EU since 2004, and Australia, Mexico, and New Zealand since 2006.
This port serves as the connection point for interfacing with your car’s computer. Besides OBD-II scanners, it’s also used for devices like insurance telematics boxes and dashcams.
If you need help locating your OBD-II port, here are guides for North American cars and for OBD-II/EOBD ports worldwide.
What is a DTC?
DTC stands for Diagnostic Trouble Code. These are error codes generated by your car’s OBD system when it detects a malfunction. OBD-II scanners read these codes to help users understand the nature of the problem. While many DTCs are standardized across vehicle makes and models, some manufacturers use proprietary DTCs specific to their vehicles.
Understanding DTC Meanings
DTCs might seem like random strings of letters and numbers, but they follow a logical structure that can provide clues about the detected issue.
The first character indicates the affected vehicle system: Powertrain (P), Body (B), Chassis (C), or Network (N). The second character is a number indicating if the code is generic (0) or manufacturer-specific (1).
The third character specifies the subsystem involved:
- 1: Fuel and air metering
- 2: Injector circuit (fuel and air metering)
- 3: Ignition system or misfire
- 4: Auxiliary emissions
- 5: Vehicle speed control and idle control systems
- 6: Computer auxiliary outputs
- 7, 8, 9: Transmission and gearbox faults
- A, B, C: Hybrid-specific propulsion faults
The fourth and fifth characters pinpoint the exact fault, ranging from 0 to 99.
OBD-II scanners typically provide descriptions of these error codes. Advanced scanners may offer more detailed information. Online resources like Google can also be helpful in deciphering DTCs. It’s important to note that there are over 5,000 possible DTCs.
Not all DTCs indicate critical problems. While they can signal serious issues, some codes may simply warn of minor anomalies like a slightly elevated engine temperature.
Choosing the Right OBD-II Scanner For Your Needs
Using an OBD-II scanner is the most effective way to gain insights into your vehicle’s operation and diagnose potential problems. It’s the same method dealerships and repair shops use.
Why not access this information yourself? OBD-II scanners come in two main types:
Handheld OBD-II scanners have an integrated screen and connect to the OBD port via a cable. Wireless OBD-II scanners plug into the OBD port and communicate with a smartphone or tablet via Bluetooth for display and operation.
Both types offer high-performance options under $200, with some available for under $30. Key factors to consider when choosing an OBD-II scanner include:
- Ease of Setup: A scanner should be quick and easy to set up for prompt diagnostics.
- Fault Code Explanation: Beyond just displaying codes, the best scanners provide clear explanations to help you understand the issue and decide on a course of action.
- I/M Readiness Check: A valuable feature for verifying emissions system readiness for vehicle inspections.
- Accuracy: Reliable and accurate results are crucial for effective diagnostics.
- Size and Weight: Portability is important, especially for roadside use and convenient storage.
- Live Data: Real-time data monitoring helps in diagnosing intermittent issues.
- Graphs: Visual data representation aids in analysis and comparison.
- Warranty: Long-term warranty and software updates ensure lasting value.
The decision between handheld and wireless scanners depends on personal preference. Consider factors like screen size (for handhelds) and the convenience of using your smartphone (for wireless).
Longevity is also key. Opt for scanners with lifetime warranties or software updates to keep pace with evolving automotive technology. For handheld scanners, prioritize screen clarity and size, and consider ruggedness for durability.
Additional features like built-in multimeters, manufacturer-specific code reading, and PDF report export can add significant value. Remarkably, many sophisticated OBD-II scanners are available for under $100, making them a cost-effective alternative to professional diagnostic services.
Our OBD-II Scanner Testing Methodology
To rigorously evaluate OBD-II scanners, I used my 2014 Audi A4 Allroad in various settings over several weeks. Each scanner was connected to the car’s OBD-II port, and I verified its ability to correctly read the Vehicle Identification Number (VIN).
For wireless scanners, I established connections with an Apple iPad Pro, Microsoft Surface, and Samsung Galaxy S9+ via Bluetooth or Wi-Fi. Handheld scanners were powered directly through the OBD-II port connection.
I measured cable lengths for handheld scanners and assessed wireless range for Bluetooth models. With the engine running, I monitored engine performance and vital systems. To simulate a fault, I disconnected the engine oil temperature sensor.
I then assessed the diagnostic details provided by each scanner, rectified the simulated fault, cleared the check engine light, and erased the error code.
Finally, I conducted road tests to evaluate each scanner’s ability to display real-time operating data such as engine speed, timing, and coolant temperature, noting whether data was presented numerically, graphically, or via simulated gauges.
Understanding OBD-II fault codes is essential. All codes consist of four numbers and a letter prefix indicating the system: Powertrain (P), Body (B), Chassis (C), or Undefined (U).
Of the approximately 5,000 standardized fault codes, generic codes (starting with ‘0’ in the numeric section) are common across all makes and models, relating to general issues like air temperature or throttle position. Manufacturer-specific codes (starting with ‘1’) are unique to specific carmakers and often indicate more detailed or brand-specific problems.
For example, a P0098 code typically indicates an issue with the intake air temperature sensor. However, a Ford-specific P1112 code for the same sensor suggests an intermittent signal, requiring sensor replacement.
