The Best Car Diagnostic Scan Tools are essential for modern vehicle owners. These ingenious devices connect to your car’s onboard computer, unlocking a wealth of information about its health and performance. Whether you’ve got a mysterious dashboard light illuminated or suspect an underlying issue, a car diagnostic scan tool, also known as an OBD-II scanner, can be your first line of defense. Instead of immediately rushing to a mechanic and incurring expensive diagnostic fees, these tools empower you to understand what’s going on under the hood yourself.
However, navigating the world of car diagnostic scan tools can be overwhelming, especially for beginners. The market is flooded with options, each boasting different features and capabilities. Having tested a wide array of OBD-II scanners over the years, we’ve gained deep expertise in identifying the top performers. We know exactly which tools deliver real value and are worth your investment. Keep reading to explore our top recommendations for the best car diagnostic scan tools available today, and delve into how these tools work and what those cryptic error codes actually signify.
Among our top selections, the Topdon TopScan stands out as a remarkably versatile and wireless option, perfect for comprehensive car diagnostics. For budget-conscious users, the Launch CR529, priced around $40, offers excellent value. If you’re seeking a professional-grade experience, and are prepared to invest accordingly, the Topdon Phoenix Lite 2 delivers advanced diagnostic capabilities comparable to those used by professional mechanics, albeit at a premium price of $799.
Here’s a quick guide to the best car diagnostic scan tools you can purchase right now.
Tom Pritchard
Tom is the UK Phones Editor at Tom’s Guide, with expertise in mobile technology and a passion for electric vehicles. He provides in-depth coverage of hardware, software, and automotive tech.
Top Car Diagnostic Scan Tools: Quick Picks
Based on our hands-on evaluations, here are the best car diagnostic scan tools currently available. Continue scrolling for detailed reviews of each product and insights into their standout features.
topdon topscan mobile OBS2 scannerTopdon TopScan Mobile OBD-II Scanner1. Topdon TopScan
The Topdon TopScan is the easiest Bluetooth car diagnostic scan tool to set up based on our testing. It packs professional-grade features into a compact, wireless design. Expect comprehensive diagnostics, repair guidance, parts information, and even predictive analysis to foresee potential problems.
Explore the Topdon TopScan in Detail
Launchcr529 obd-ii scanner on white backgroundLaunch CR529 OBD-II Scanner on White Background2. Launch CR529
The Launch CR529 is a small yet potent car diagnostic scan tool offering a comprehensive suite of features typically found in higher-priced models. Benefit from lifetime support and software updates, making it an exceptionally valuable tool for the price.
Discover More About the Launch CR529
topdon phoenix lite 2 obd-ii scanner and tablet on a white backgroundTopdon Phoenix Lite 2 Professional Car Diagnostic Scan Tool3. Topdon Phoenix Lite 2
Resembling a rugged tablet, the Topdon Phoenix Lite 2 is a professional-grade car diagnostic scan tool designed for both experienced mechanics and car enthusiasts. Its robust build and advanced functionalities make it a top choice for those needing a powerful and durable scanner.
Learn More About the Topdon Phoenix Lite 2
best obd2 scannersAncel BD310 Dual-Purpose OBD2 Scanner and Dashboard Display4. Ancel BD310
The Ancel BD310 is a versatile car diagnostic scan tool that doubles as an auxiliary dashboard display. In addition to standard OBD-II scanning, it can project real-time engine data onto your dashboard, combining functionality with convenience.
Read More About the Ancel BD310
carly obd scanner grid imageCarly OBD-II Scanner with Companion App Interface5. Carly OBD-II Scanner
The Carly OBD-II Scanner’s effectiveness is highly dependent on your vehicle’s make, with brands like VW, BMW, and Ford benefiting the most. Its standout feature is its exceptional companion app, offering extensive customization and professional-level diagnostic tests.
Explore the Carly OBD-II Scanner App Features
Understanding Car Diagnostic Scan Tools: What Makes Them the Best?
Why Trust Tom’s Guide? Our team dedicates countless hours to rigorously evaluate and review products, ensuring we recommend only the best options. Learn more about our testing and review process.
Best Mobile Car Diagnostic Scan Tool
topdon topscan obd scanner with bluetooth
(Image credit: Topdon)
1. Topdon TopScan
Ideal for In-Depth Vehicle Analysis
Read our expert review of the Topdon TopScan
Key Specifications
- Display/Size: None
- Bluetooth/Handheld: Yes/No
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Number of Keys: None
- Warranty: 2 years
- Size: 3.2 x 2.0 x 1.1 inches
- Weight: 2.6 ounces
Advantages
- Exceptional automotive diagnostic coverage
- Real-time live data monitoring
- Unique performance indicators
- Comprehensive maintenance item coverage
Disadvantages
- Bulky and heavy transmitter
- Subscription required for some features after one year
The Topdon TopScan may appear unassuming at first glance, but this compact car diagnostic scan tool is packed with features that surpass many competitors in its class. More than just a standard Bluetooth OBD-II module transmitting data to your smartphone app, the TopScan goes above and beyond typical scanners. I was particularly impressed by its ability to delve into vehicle performance and efficiency metrics, extending beyond basic fault detection and I/M Readiness tests. It can even estimate crucial performance figures like horsepower and torque.
Remarkably, the TopScan offers capabilities often absent in car diagnostic scan tools costing ten times as much. Whether you aim to fine-tune your vehicle’s performance or ensure its roadworthiness, the Topdon TopScan is an invaluable addition to your toolkit.
Read our comprehensive Topdon TopScan review
Best Budget-Friendly Car Diagnostic Scan Tool
Launch cr259 obd–ii scanner
(Image credit: Future)
2. Launch CR529
Top OBD-II Scanner Under $50
Read our expert review of the Launch CR529
Key Specifications
- Display/Size: Color/ 2.8-inches
- Bluetooth/Handheld: No/Yes
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Number of Keys: 8
- Warranty: 1 year
- Size: 6.5 x 3.8 x 1.2 inches
- Weight: 11 ounces
Advantages
- Highly affordable
- Lifetime free updates
- Easy pre-inspection report generation
Disadvantages
- Lacks manufacturer-specific codes
- Feels somewhat heavy
- Limited 1-year warranty
In my assessment, the Launch CR529 is arguably the best value car diagnostic scan tool on the market. Its $38 price point is just the beginning; the range of diagnostic features it delivers for this cost is truly remarkable. I was genuinely surprised by the level of functionality packed into such an affordable device.
Certainly, compromises are made to achieve this price. The CR529 doesn’t support manufacturer-specific diagnostic codes and has a slightly heavier feel. However, it still offers essential features like live data streaming, an instant inspection function, and a surprisingly detailed view into your vehicle’s internal systems. Furthermore, lifetime updates ensure the scanner remains useful for years to come without subscription fees.
While the CR529 might not cater to professional mechanics seeking advanced features, it’s an excellent choice for most car owners and DIY enthusiasts looking for a reliable and budget-friendly car diagnostic scan tool.
Read our full Launch CR529 review
Best Professional-Grade Car Diagnostic Scan Tool
topdon phoenix lite 2 obd2 scanner over car engineTopdon Phoenix Lite 2 OBD2 Scanner Over Car Engine Bay(Image credit: Future)
3. Topdon Phoenix Lite 2
Bridging the Gap Between DIY and Professional Diagnostics
Read our expert review of the Topdon Phoenix Lite 2
Key Specifications
- Display/Size: Color/8-inch
- Bluetooth/Handheld: Yes/Yes
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Number of Keys: Touchscreen
- Warranty: 2 years
- Size: 10.2 x 7.2 x 1.7 inches
- Weight: 2.6 pounds
Advantages
- Professional-level OBD scanner capabilities
- Wireless handheld with Wi-Fi and Bluetooth connectivity
- Large 8-inch touchscreen display
- Extensive suite of diagnostic tests and live data options
- Includes adapters and protective hard case
Disadvantages
- Large, heavy, and can be cumbersome
- High price point
- Subscription required after two years for updates
The Topdon Phoenix Lite 2 car diagnostic scan tool represents a significant investment, costing more than many other capable OBD-II scanners. However, it delivers exceptional value for the money, offering a blend of features suitable for both amateur car enthusiasts and professional mechanics.
A standout feature of the Phoenix Lite 2 is its completely wireless operation. The control pad connects via Bluetooth to a receiver plugged into the car’s OBD port, providing unparalleled freedom of movement around the vehicle. While the scanner itself is substantial in size and weight, it includes a kickstand and rugged construction designed to withstand demanding workshop environments.
Beyond basic diagnostics, it offers advanced features like live data graphing, detailed fault information, and capabilities rarely found in lower-priced scanners. Keep in mind that firmware updates are included for two years, after which an annual subscription of $495 is required.
Read our in-depth Topdon Phoenix 2 Lite review
Best Dual-Purpose Car Diagnostic Scan Tool
Best OBD-II scanners: Ancel BD310
Ancel BD310 (Image credit: Tom’s Guide)
4. Ancel BD310
A Versatile OBD-II Scanner with Added Functionality
Read our expert review of the Ancel BD310
Key Specifications
- Display/Size: Color/2 inches
- Bluetooth/Handheld: Yes/Yes
- I/M Readiness Test: Yes
- Live Data Display: Yes
- Number of Keys: 4
- Warranty: 3 years
- Size: 5.1 x 2.4 x 0.6 inches
- Weight: 5.4 ounces
Advantages
- Lightweight and compact design
- Functions as both a scanner and secondary car display
- Offers handheld and Bluetooth scanning options
Disadvantages
- Minimalist interface
- Small screen size
The Ancel BD310 car diagnostic scan tool is designed for dual functionality. It operates as a standard handheld scanner and, when paired with a smartphone via Bluetooth, transforms into a secondary display for your car, projecting essential engine data within the cabin.
We found the BD310 exceptionally convenient due to its small and light form factor, easily stored in a glovebox. The 2-inch display is admittedly small, and the four-key interface felt somewhat clunky initially, but it didn’t hinder the process of diagnosing vehicle issues.
Its 56-inch cable is ideal for working under the hood, and the BD310 performs essential diagnostic tasks, including I/M readiness tests and displaying performance metrics like coolant temperature, engine timing, and RPM.
Read our complete Ancel BD310 review.
Best Car Diagnostic Scan Tool with Companion App
carly obd 2 scanner design
(Image credit: Carly)
5. Carly OBD-II Scanner
Scanner Performance Varies by Vehicle Make, App is Consistently Excellent
Read our expert review of the Carly OBD-II Scanner
Key Specifications
- Display/Size: None
- Bluetooth/Handheld: Yes/No
- I/M Readiness Test: No
- Live Data Display: Yes
- Number of Keys: None
- Warranty: Lifetime
- Size: 2.9 x 1.5 x 0.7 inches
- Weight: 0.7 ounces
Advantages
- User-friendly interface
- Extensive customization options
- Live data display
- Covers maintenance and repairs
- Lifetime warranty and updates
Disadvantages
- Feature availability varies across car models
- App subscription can be costly
The Carly OBD Scanner stands out for its impressive features and, particularly, the exceptional quality of its companion app. While many Bluetooth scanners offer rudimentary apps, Carly provides one of the most sophisticated and user-friendly app experiences we’ve encountered.
Beyond basic fault code reading and clearing, the app offers repair assistance, tools for pre-purchase used car inspections, and a lifetime warranty, a rare and valuable offering.
However, the range of features supported varies significantly depending on your car’s make and model. Compatibility should be verified before purchase. Additionally, while the app is outstanding, accessing advanced OBD features requires an ongoing subscription, which can become expensive over time.
Read our full Carly OBD scanner review
Other Car Diagnostic Scan Tools We Evaluated
Innova CarScan Mobile 1000 review” data-widget-type=”deal” data-render-type=”editorial”>Innova CarScan Mobile 1000 (★★★★☆)
The Innova CarScan Mobile 1000 is a highly innovative Bluetooth car diagnostic scan tool, inheriting Innova’s renowned features like predictive diagnostics in a completely wireless, phone-based format. Its incredibly simple setup process further enhances its appeal as a Bluetooth-only option.
Read the full Innova CarScan Mobile 1000 review
ThinkCar ThinkDiag TKD01 (★★★★☆)
ThinkCar ThinkDiag TKD01 (★★★★☆)
While larger than typical Bluetooth OBD-II devices, the ThinkCar ThinkDiag TKD01’s robust build makes it exceptionally durable. It offers extensive manufacturer-specific error codes and advanced fault-code analysis capable of resolving minor issues without mechanic intervention. A $40 subscription is required after the first year.
Read our full ThinkCar ThinkDiag TKD01 review.
Autel AutoLink AL539 (★★★☆☆)
The Autel AutoLink AL539 car diagnostic scan tool is specifically designed for electrical system diagnostics, featuring a built-in multimeter. It excels at identifying electrical faults like damaged wiring, short circuits, and blown fuses. It also provides a wide array of live data and pre-inspection readiness checks.
Read our full Autel AutoLink AL539 review
Frequently Asked Questions About Car Diagnostic Scan Tools
What exactly is a Car Diagnostic Scan Tool (OBD-II Scanner)?
If you’ve ever wondered how mechanics pinpoint car problems, it’s not through manual disassembly and inspection. They use car diagnostic scan tools, plugged into your vehicle’s OBD port, to access data from the onboard computer.
These tools, at their core, read and interpret error codes generated by your car when it detects an issue. More sophisticated models monitor vehicle systems in real-time and can even predict potential future problems. Using a car diagnostic scan tool empowers you to understand your car’s issues proactively.
What is the OBD-II Port and Where is it Located?
The On-Board Diagnostics Version Two (OBD-II) port has been a standard feature in most 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 interface point to your car’s computer. Various devices can connect to it, including car diagnostic scan tools, insurance telematics devices, and increasingly, dash cams.
If you’re unsure of your OBD-II port’s location, here’s a guide to finding the OBD-II port in North American vehicles. For worldwide locations, refer to this guide on finding OBD-II/EOBD ports globally.
Understanding DTCs: What are Diagnostic Trouble Codes?
DTC stands for Diagnostic Trouble Code. These are error codes generated by a vehicle’s OBD system when it detects a malfunction. Car diagnostic scan tools read these codes, enabling users to diagnose car problems. While many DTCs are standardized across vehicle makes and models, some manufacturers use proprietary DTCs specific to their vehicles.
Decoding DTCs: What Do Car Error Codes Mean?
DTCs may seem like random characters, but they follow a logical structure that reveals the type and location of the problem. Understanding this structure can provide initial clues about the detected errors.
The first letter indicates the affected vehicle system: Powertrain (P), Body (B), Chassis (C), or Network (N). The second character, a number, specifies whether it’s a generic code (0) or a manufacturer-specific code (1).
The third character further pinpoints the specific subsystem involved:
- 1: Fuel and air metering
- 2: Injector circuit issues related to fuel and air metering
- 3: Ignition system or misfires
- 4: Auxiliary emissions control
- 5: Vehicle speed control and idle control systems
- 6: Computer auxiliary outputs
- 7, 8, 9: Transmission and gearbox faults
- A, B, C: Hybrid propulsion system faults
The fourth and fifth characters provide the precise fault details, ranging from 0 to 99.
Car diagnostic scan tools translate these codes into understandable descriptions. Advanced models offer more detailed information. Online resources like Google can also help decipher DTCs, as there are over 5,000 potential codes.
It’s important to note that not all DTCs signal critical issues. Some may indicate minor problems, such as a slightly elevated engine temperature.
Choosing the Best Car Diagnostic Scan Tool: Key Considerations
When seeking insights into your vehicle’s operation or troubleshooting issues, a top-tier car diagnostic scan tool is invaluable.
Just as dealerships and repair shops use these tools, you can also access the same diagnostic power. Car diagnostic scan tools come in two primary types:
Handheld OBD-II scanners: These have integrated screens and connect to the OBD port via a cable. Wireless OBD-II scanners: These plug into the OBD port and communicate wirelessly via Bluetooth to a smartphone or tablet for display.
Regardless of the type, numerous high-performance car diagnostic scan tools are available for under $200, with some even below $30. Key features to consider when selecting the best car diagnostic scan tool include:
- Ease of Setup: A user-friendly setup is crucial for quick diagnostics.
- Fault Code Interpretation: The best tools not only display fault codes but also provide clear explanations for effective troubleshooting.
- I/M Readiness Check: Essential for emissions testing, this feature confirms if your vehicle will pass inspection.
- Accuracy: Reliable and accurate readings are paramount for correct diagnoses.
- Size and Ergonomics: A compact and easily handled scanner is more likely to be used regularly.
- Live Data Streaming: Real-time data monitoring helps identify intermittent issues.
- Data Graphing: Visual data representation, especially graphs, aids in analyzing trends and changes over time.
- Warranty: A robust warranty, ideally lifetime or extended, ensures long-term reliability.
Deciding between handheld and wireless options is the first step. Consider whether you prefer a dedicated screen or the convenience of using your smartphone.
Longevity is another factor. Opt for scanners with lifetime updates or warranties to keep pace with evolving automotive technology.
For handheld scanners, prioritize screen size and clarity, aiming for a large, bright, icon-driven display. If durability is a concern, ruggedized models with protective bumpers are advisable.
Additional features to look for include electrical multimeter functionality, manufacturer-specific code reading, and PDF report export capabilities.
The affordability of sophisticated car diagnostic scan tools, often under $100, makes them a cost-effective alternative to professional mechanic diagnostic fees, typically costing at least an hour’s labor.
Our Car Diagnostic Scan Tool Testing Methodology
To rigorously test car diagnostic scan tools, I used my 2014 Audi A4 Allroad over several weeks in both garage and road conditions. Each scanner was connected to the car’s OBD-II port, verifying its ability to read the Vehicle Identification Number (VIN).
For wireless scanners, connections were established with an Apple iPad Pro, Microsoft Surface, or Samsung Galaxy S9+ via Bluetooth or Wi-Fi. Handheld scanners were simply plugged into the OBD-II port for power.
Cable lengths (for handhelds) and wireless ranges were measured. With the engine running, engine and system parameters were monitored. Subsequently, the engine oil temperature sensor was disconnected to induce a fault.
The scanner’s diagnostic details were assessed. After resolving the simulated issue, the check engine light was cleared, and the error code erased using the scan tool.
Finally, on-road testing evaluated the scanner’s ability to display real-time operational data such as engine speed, timing, and coolant temperature, noting whether data was presented numerically, graphically, or via gauges.
Understanding fault codes is crucial. All diagnostic trouble codes (DTCs) consist of four numbers and a letter prefix indicating the system: Powertrain (P), Body (B), Chassis (C), or Undefined (U).
Of approximately 5,000 possible DTCs, generic codes (starting with 0 numerically) are universal across vehicles and relate to common issues like air temperature or throttle position. Manufacturer-specific codes (starting with 1 numerically) are unique to specific carmakers, often indicating specialized hardware or more detailed problem analysis.
For example, a P0098 code generally indicates a problem with the intake air temperature sensor. Conversely, a Ford-specific P1112 code points to intermittent intake air temperature sensor readings, suggesting sensor replacement.
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