Want to identify your car’s faults quickly and easily? An OBD-II device might be just what you need
Today’s vehicles are festooned with tech, one of the most useful being an OBD-II port – OBD standing for On-Board Diagnostics – and now the days when you’d need a finely tuned ear and deft mechanical prowess to identify a fault with a car are long gone.
OBD-II ports started to be used in 1996 to allow access to the endless data a car or van generates – like a window into your car’s brain – including any error codes resulting from faults in a vehicle’s myriad electronically managed systems, such as fuel injectors, dashboard electronics, engine sensors, or electric windows, to name just a few. They may even carry data about how you drive, which could include the car’s mileage as well as speed, braking and acceleration.
By using an OBD-II scanner – a small device that plugs into this innocuous-looking socket, usually hidden away under the dashboard – you can read the car’s computerised fault logs to see precisely what’s wrong, so you can either set about fixing the fault yourself, or you can tell a mechanic exactly what needs to be looked at.
These mandatory connections are standard across all makes and models. With the falling prices for the tech to access these fault codes and the concomitant rise of smartphones, Bluetooth connectivity and the internet, there is now a market for easy-to-use OBD-II readers suitable for the home mechanic, effectively ending the need to travel to a garage every time an engine management light appears.
Following our buying guide below, we’ve compiled a list of the best devices to suit all kinds of budgets and needs.
Best OBD-II devices: At a glance
|Best budget OBD-II scanner
|Torque Pro Fault Scanner (~£13)
|Check price at Amazon
|Ancel BD310 (~£79)
|Check price at Amazon
|Best for flexibility
|Veepeak Mini BT scanner (~£17)
|Check price at Amazon
|Best cheap Android tablet
|NEXAS Nexlink (~£26)
|Check price at Amazon
How to choose the best OBD-II device for you
What’s the difference between OBD and OBD-II?
On-board diagnostics evolved. Quite simply, OBD-II – also known as OBD2 – is a more advanced, more sophisticated version of the relatively short-lived OBD system. Crucially, OBD-II is now the standard access point in every new car and van sold.
Can I damage my car with an OBD-II scanner?
It’s highly unlikely. The vast majority of commercial OBD-II scanners only read the car’s data and are unable to write data back onto the car’s systems. The OBD-II socket does have the capacity to reprogramme all sorts of parameters, but the software required tends to be advanced, expensive and requires significant know-how. So the risk is extremely low with the kind of OBD-II scanners we’re looking at here.
However, many do offer the ability to clear fault codes. You should take care when doing so because these errors are logged for a reason. Clearing a code without resolving the underlying issue could just mean it will reappear seconds, hours or even weeks later, and you could be storing up problems for yourself down the line.
What features should I look for?
If you have a specific issue with your car that you’re hoping to diagnose, make sure that the device you pick supports that component. It might feel a bit like eating acronym soup, what with the ABS (brakes), SRS (airbags) and TPMS (tyre pressure). However, not all OBD-II devices are created equally, and some won’t cover all of these components.
If you’re looking for a wireless device, make sure the device is compatible with your phone’s operating system – most are Android-friendly but it’s worth checking which version of Android it’s compatible with. If you’re looking to clear a malfunction indicator light (MIL), ensure the device you choose enables you to clear codes.
Finally, some devices will automatically read your car’s vehicle identification number (VIN), while some will require you to type it in. Just so you know, since your car can fail its MOT test if it doesn’t meet emissions standards, you’ll see a lot being made of “i/M readiness” as a feature – this is a way of checking if your vehicle is ready for emissions testing.
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How much should I spend on an OBD-II scanner?
Working out which OBD-II device will suit you best means figuring out what your budget is. Prices can range from £10 for the most basic devices to over £4,000 for professional tools. If you just want to check the error codes to protect yourself from the price-gouging of any yarn-spinning cowboy mechanics, then a cheaper device should be sufficient.
However, if you’re more of a home mechanic and looking to tinker, you might wish to invest in something with a bit more functionality. The good news is that prices have been coming down: with a wider range of apps able to use your smartphone’s interface to control the device, the hardware units themselves are often smaller and much cheaper to produce.
What should I avoid?
A word of warning: be wary of those cheaper, easy-to-produce hardware units. Like many electronic products, there’s a fair share of shady brown stuff out there on the market. A lot of these devices aren’t legit, often being no more than a plastic shell without any connectivity, and even if they do have connectivity, there’s a possibility the software in the app isn’t licensed or won’t be compatible with your vehicle.
You might also find, with some cheaper models, that the device indicates a fault without giving any more information unless you pay for it, creating a false economy with the initial low purchase price.
Where can I find my OBD-II port?
The diagnostics port can usually be found on the driver’s side of the car, in or about the steering wheel, down near your knees – you might need to get out of the car and crouch down since the port can be tucked away. Be aware that some ports are covered too, so you might see a finger hole inviting you to pull the relevant panel off. If you still have the manual for your specific model car, you’ll find the exact location and how to access your OBD-II port there.
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The best OBD-II scanners you can buy in 2024
1. Carly: Best OBD-II scanner for home mechanics
Price when reviewed: From £75 | Check price at MyCarlyYes, there are cheaper OBD-II scanners out there, but few are as user-friendly as Carly. Basic and Premium schemes are available, the difference being that the Premium pack boasts features specific to your car and, at the time of testing, was actually cheaper than the Basic offering. Smart Mechanic costs an additional £36 and, as we’ll see, is worth the money.
Documentation in the box is minimal, the unit being as close to plug-and-play as it’s possible to get, but there’s a good amount of support online. We downloaded the iOS and the Android app, added our cars through the apps – which took a couple of minutes – then plugged Carly into the OBD-II socket and had no problem connecting via Bluetooth.
We liked the clear interface and the ability to detect current and historical fault codes. The Smart Mechanic function provides thorough and easy to understand – if generic – information on 6,000 fault codes and how to fix the issues that frequently generate them. Armed with that information, you can Google that fault for your specific car.
The scanner can also check for mileage tampering, which means it could be indispensable when buying a used car, and on certain models can unlock hidden features such as activating ‘coming home’ headlights. Battery monitoring and service and maintenance reminders are the icing on a very impressive cake.
Key specs – Wired/wireless connection: Wireless; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Smartphone; Windows/Apple/Android: All; Oil service reset: Yes
2. Torque Pro Fault Scanner: Best budget OBD2 scanner
Price when reviewed: £13 | Check price at AmazonThe Torque Pro Elm 327 is as basic as it gets. Download the Torque app – the Lite version is free, but the Pro version is still less than a fiver – from the Google Play store (there’s no Apple App Store support yet) and, like all the other devices on this list, simply plug and play. Compatible with 98% of cars, the Pro Elm 327 is all about giving you confidence at the garage.
This 30-gram dongle is also capable of more than it first appears, even if you have to pore over a few YouTube videos to figure out what the information means. It will clear most basic error codes, though it doesn’t have the capacity to configure SRS. But that’s understandable, since SRS stands for “supplemental restraint system” and relates to the airbags. Finally, it also comes with a 12-month no-quibble warranty.
Key specs – Wired/wireless connection: Wireless; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Smartphone; Windows/Apple/Android: Android only; Oil service reset: No
3. ANCEL BD310: Best all-round OBD-II scanner
Price when reviewed: £70 | Check price at AmazonThe Ancel BD310 is a lightweight mid-priced scanner with a stylish design. Providing comprehensive reports, it’s the best all-rounder on this list as it offers the best of both worlds: there’s a wired, screen-based component, but you can also connect via Bluetooth to the Ancel app – available on iOS and Android – where more features are offered. It even offers telematics data, which lets drivers see how harsh braking and acceleration affects their vehicle and their fuel consumption through a live data feed.
The Ancel BD310 doesn’t automatically detect your car’s VIN, and there’s no way of adjusting the brightness of the screen, but, that said, the price includes a vent mount, a warranty and lifetime customer service, which makes it very good value.
Key specs – Wired/wireless connection: Both; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Both; Windows/Apple/Android: All; Oil service reset: Yes
4. Veepeak Mini Bluetooth Scan Tool: Best for flexibility
Price when reviewed: £16 | Check price at Amazon
Another budget-friendly buy, the Veepeak Mini Bluetooth Scan Tool works for both petrol and diesel OBD-II ports. Compatible with both Windows and Android, the Veepeak is more of a middleman since there’s no Veepeak app. However, it is compatible with other apps – such as DashCommand, Dr Prius, and Torque Pro (see above) – so drivers may need to factor the cost of an app into the total price.
The Veepeak Mini is lightweight and compact, making it handy enough to keep in the glovebox. So if you have any car trouble while away from home, you can get a reading there and then, enabling you to make a decision immediately. Reassuringly, the Veepeak Mini comes with a 30-day money-back guarantee too.
Key specs – Wired/wireless connection: Wireless; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Smartphone; Windows/Apple/Android: Windows and Android; Oil service reset: No
5. Autel ML629 OBD-II Scanner: Best for checking brakes and airbags
Price when reviewed: £116 | Check price at AmazonAutel is a brand synonymous with automotive diagnostic tools. The company has a wide range of OBD-II devices, from basic cheaper options through to comprehensive professional machines. There’s also compatibility with a broad number of car models. The Autel ML629 is very much a mid-range product, where a consumer-friendly price point meets a fair amount of functionality.
The ML629 has a wired connection and a robust design, and it’s easy to use, with soft buttons to navigate around the full-colour screen. The instructions aren’t the clearest but, with a bit of patience, the ML629 is fairly intuitive. Its library of DTCs isn’t just limited to ABS (braking) and SRS (airbags), but also covers the engine and the transmission. It’s also useful that Autel enables you to print off the information.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Display; Windows/Apple/Android: Windows and Apple; Oil service reset: Yes
6. LUCKYDIY OBD-II Reader: Best budget handheld scanner
Price when reviewed: £16 | Check price at AmazonYou can ignore the strange name because this unit is common on Amazon under a range of brands. But, whichever one you choose, it’s a powerful and easy-to-use handheld unit. There’s no fiddling around trying to connect to your smartphone; you simply plug the cable into the OBD-II socket and the unit fires up. Once you’ve got your head around the menus, it’s simple enough to navigate and it’s pretty quick to respond to your inputs. The screen is a little bit ‘1980s Casio calculator’, but the digits are clear, even if there’s no backlight.
The features are basic, yet they cover everything that many drivers will ever need. The diagnostic menu allows you to read and erase fault codes and view i/M Readiness codes, which relate to a vehicle’s emission control systems. The vehicle information menu displays real-time driving information, such as coolant temperature and engine speed, as well as the vehicle’s VIN number. There’s even a database of fault code numbers.
It’s far from the fanciest scanner to look at and it lacks many features of the more expensive units here, but, as a tool that does the basics quickly and cheaply, it’s highly recommended.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes (DTC only); Display or smartphone interface: Display; Windows/Apple/Android: N/A; Oil service reset: No
7. NEXAS NexLink: Best for iPhone users
Price when reviewed: £26 | Check price at Amazon
NEXAS is another company with diagnostic scanning credentials from the commercial side of the automotive industry. The brand has created the NEXAS NexLink, a Bluetooth dongle. However, this one is compatible with iOS, as well as Android and Windows. Weightier and made from more robust plastic than some of the other dongles featured here, the build quality is better, though this quality is reflected in the price.
Like the Veepeak Mini, the NEXAS NexLink doesn’t have its own app, so you’ll need to factor in the additional cost of DashCommand, Torque Pro, Carista or OBDFusion to get the full benefit of this little device. NEXAS claims that the Nexlink is “hacker-proof” due to a unique security mechanism. The device also supports motorcycles, giving it a wider appeal.
Key specs – Wired/wireless connection: Wireless; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Smartphone; Windows/Apple/Android: All; Oil service reset: No
8. iCarsoft CR V2.0 Diagnostic Scan Tool: Best for bigger budgets
Price when reviewed: £159 | Check price at LJM DirectThe iCarsoft CR V2.0 is an effective tool that covers a broad range of system checks, including Oil Service Reset, Electronic Parking Brake (EPB) and Battery Management System (BMS), among others. Supporting petrol, diesel and some electric vehicles, it can store up to ten manufacturers’ data in multiple languages. You get to specify which, as you select them during setup.
Although the device is only Windows-supported, it automatically detects the device’s ID on the scan tool, and the car’s VIN when connected to the OBD-II port, making it very easy to use. The iCarsoft CR V.20 is practical too: the 4in screen is sufficiently big, the colours are bright, and the build quality feels durable. While it’s a pricier option, if you have multiple cars in the house and you like to be hands-on, this offers great value.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Display; Windows/Apple/Android: Windows only; Oil service reset: Yes
9. Autel MaxiDiag MD808 Pro: Best for going pro
Price when reviewed: £289 | Check price at AmazonThe five-foot extension cable with the MaxiDiag MD808 Pro definitely makes things a lot easier when you’re trying to figure out what’s up with a malfunctioning car. Although 1.75kg is fairly hefty for a handheld device, the cable aids your ability to prop it on the engine bay. The colour display is easy to navigate and can be seen in most daylight conditions too.
The price tag on the MaxiDiag will be prohibitive for most drivers – if you simply want to save money on needless dealership trips, other devices can do that for less. However, the MaxiDiag MD808 comes into its own for home mechanics. With the ability to read DTCs and reset a variety of systems across a very broad range of cars, the MaxiDiag is incredibly comprehensive. And, for that reason, it’s worth reading the manual properly before use.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or Smartphone interface: Screen; Windows/Apple/Android: All; Oil Service Reset: Yes
10. Foxwell NT680 Pro Diagnostic Car Scan Tool: Best for workshop environments
Price when reviewed: £389 | Check price at Halfords
Acting as a replacement for the NT644 Pro, this high-end model from Foxwell is the sort of professional handheld device you might find in a small local garage, but it’s just as useful for skilled amateur mechanics and home tinkerers.
Everything you need to get started is in the handy carry-case, including the physical cable to connect to the OBD-II port. Once you’re up and running, the device offers coverage for most vehicle systems – especially for models from European, Asian and North American manufacturers – enabling you to read and clear of most common DTCs, including those from the engine, SRS (airbag), ABS, automatic gearbox, central locking, climate control and more. It also allows for some more advanced fault clearing, like the ability to reset airbag warnings and change the default tyre size, as well as more advanced features, like preparing for an EVAP test or headlamp adjustment.
The TFT colour display is bright and easy to use, and the device allows for the recording of live sensor data, as well as graph merging for easier fault diagnostics. This is where things get more complicated, but you’ll be amazed how much of a reference tool the internet is these days. A 16GB micro SD card allows for data to be stored and uploaded to laptops later. Plus, a USB connection means the device can be updated when new software patches surface.
It’s not the cheapest option on this list but it is built tough, designed to withstand the rigours of a workshop environment, and there’s not much the device doesn’t deal with.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Display; Windows/Apple/Android: None; Oil service reset: Yes
11. Laser OBDII/EOBD Fault Code Reader: Best for basic fault code reading
Price when reviewed: £38 | Check price at Halfords
Sometimes, a wired code reader is the simplest – there’s no annoying app to download or smartphone to pair – but the downside is that you will have to go and look up the meaning of the code, either online or in your vehicle’s manual.
Let’s be clear: this diminutive plastic handheld – featuring a backlit LCD screen that’s easy to read in most working conditions – is just a very basic fault code reader, and that is reflected in the price.
Simply plug it in and it will throw up most error codes for any vehicle manufactured since 1996. It will also automatically read the VIN of any car released since 2022 or thereabouts. It’s also possible to use it to turn off the malfunction indicator light (MIL) for most codes it unearths.
Ideally, this piece of kit will allow you to determine the problem with your vehicle, so you can order the appropriate parts (if needed) and save yourself the associated diagnostics fees a local garage would normally charge. We tested this on a Volkswagen Transporter T5.1 with an intermittent engine warning light and it managed to hone the issue down to a fault with the diesel particulate filter, certainly saving us some cash as we could order a new one and have it fitted quickly for less.
Of course, those with some mechanical knowledge and a willingness to get ‘hands-on’ can use this cheap and cheerful piece of tech to get to the bottom of most common issues before fixing it themselves. Just expect to have to go research the fault code’s meaning before breaking out the spanners.
Key specs – Wired/wireless connection: Wired; Read DTCs: Yes; Clears DTCs, inc. MIL: Yes; Display or smartphone interface: Display; Windows/Apple/Android: None; Oil service reset: No