CARLY Scanner review – the cheat sheet to buying a used car


► CARLY OBD II Scanner tested
► A must-have tool for buying a used car

► View our guide to car diagnostics here

Carly is a pioneer in simplifying car diagnostic systems. This little pocket-sized item can gather hundreds, if not thousands, of data points throughout a vehicle before compiling them onto your phone via the Carly app, telling you any detected faults.

The device itself uses a 32-bit-ARM processor that reads the many electronic units from a VW Polo to a Bentley Mulsanne. Any petrol car built to be sold in the EU from 2001 (2004 for diesel) will feature the required OBD II port that the Carly plugs into, making it a versatile option. Any diagnostic tool like this is designed to detect faults early and save a plethora of cash on car repairs.

Carly aim goes one step further than other OBD II scanners, detecting mileage discrepancies via the Mileage Check and making the device both temptingly small and affordable. All of this combined makes it a fabulously appealing device, and with a premium subscription, a deep dive of every nook of your car is seamless.

Aaron Hussain conducted this review of the Carly Scanner. As a classic car owner and enthusiast, he is adamant that preventive maintenance and issue monitoring are key to protecting a vehicle’s longevity, no matter how small, large, old, or new.

Verdict: A pocket-sized catalyst for preventative maintenance but a couple of small quirks in the app stop it from being perfect.

Score: 4/5

Carly Scanner product shot

Carly Scanner: what works well

The connected Carly App on a mobile phone

Chief among the pros is the sheer simplicity of the thing. Find the OBD II slot (it’s usually under the steering wheel) and insert the device before it’ll beaver away. It’ll then generate the readings on the app, all presented in an easy-to-digest format – there’s no need to crack out the Haynes manual here. It takes time if a car has more electronic modules than others, so you have to expect to wait for around 5-10 minutes on average. You can then browse accordingly, deciphering which points need addressing and which you’d like to clear.

But what really comes into its own is Carly’s mileage check. Essentially, it can spot mileage discrepancies in cars by reading different parts of the car’s brain and detecting if things don’t quite line up or have been naughtily rolled back. Thankfully, the cars we tested it on showed legitimate information throughout. But it’s a useful tool if you’re going to check out a used car.  

The best thing, however, is its versatility. All cars from 2004 onwards have to be equipped with an OBD II port, which means any car you can think of is compatible with the Carly. If you really wanted to, you could plug a Carly Scanner into an Aston Martin Vulcan or a Shelby Ultimate Aero. For buying almost any car made in this Millennium, it’s a clever little tool to bring along for the test drive.

Carly Scanner: what’s okay

The Carly OBD II scanner installed in a car

One thing to keep in mind regarding these diagnostic scans is that a load of data may not have been cleared if it was plugged in and diagnosed before. It’s ultimately down to the user to clear the codes as and when it’s appropriate.  

So, while there can be a lot of issues to look through on a vehicle, it’s important to be selective of which ones are important and not. But it is nice in that respect that the Carly doesn’t skip issues.  

The other aspect that’s open to interpretation is the brand’s approach to value for money. You can spend just under £75 on the basic product, which includes the ability to plug it in and diagnose your car. Access to the Carly Used Car Check is free for everyone, provided you download the app and set up an account. 

The premium package begins at just under £134, and you can add the Smart Mechanic optional extra, essentially a forum with expert advice on many different cars and fault indications, for a grimace-inducing £35.99.  

Carly Scanner: what’s bad?

The Carly OBD II scanner installed in a car

With many different electronic components and modules to read, Carly will naturally take its time to analyse each one. Whilst it’s understandable from a tech perspective, it is still quite annoying when you have to wait for up to ten minutes to generate a diagnosis on a car. It’ll take longer to read through a tech-packed Mercedes S-Class than it will a Toyota GT86, so the length of reading is always going to be car-dependent.  

The more mechanically gifted wrenchers among us will probably bemoan the slow response times and dumbed-down diagnostics, but for the average car buyer, it can be the difference between a good car and a lemon.

Away from the scanner itself, if you begin exploring the Carly app, you’re unfortunately met with a few issues. Chief among these is a pop-up which asked for my feedback, requiring at least ten characters. Filling in that box was the only way to get rid of it, and it’s an annoyingly persistent little thing. This comes up during the Used Car Check most of the time, so it shouldn’t affect diagnostic results.  

The weirdest issue is on the car selector menu: the Audi RS2 was apparently built between 2000 and 2005. Hmmm.  

Other products to consider:

TOPDON Topscan OBD2 Scanner, RRP £69.99
Autel OBD2 Code Reader, RRP £29.99
Bosch Automotive Tools OBD 1150 Trilingual Scan Tool, RRP £87.78

How we tested the Carly Scanner: 

The Carly Scanner was tested on a few different cars to test the versatility between each. We analysed the user-friendliness of the app as well as how easy it is to plug in and out of. We didn’t have the facilities to go about repairing and clearing diagnostic messages.  

Who tested the Carly Scanner? 

The Carly Scanner was tested by Aaron Hussain. As an avid believer of preventative maintenance on his classic Mercedes, the Carly setup was a perfect feeler of his routine when he eventually gets a more modern daily driver.  

Just so you know, whilst we may receive a commission or other compensation from the links on this website, we never allow this to influence product selections – read why you should trust us


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