2023 Carly OBD Fault Code Reader Review

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Reading Time: 6 minutes

Now, you’ve probably seen Carly being advertised on a million carTubers channels over the last few years, but there are very few written reviews of what it’s actually like to use. So here it is!


What is it?

Carly is a car diagnostic tool that connects to your smartphone via Bluetooth and provides insight into your vehicle’s health and performance. It allows you to scan your car’s systems, view live data, customise various features, and get expert guidance from the Smart Mechanic feature. Carly is compatible with most OBD2-compliant vehicles made after 2000, and it works with both iOS and Android devices.


How does Carly OBD work?

Carly works by plugging a small adapter into your car’s OBD port, usually under the dashboard. The adapter communicates with your smartphone via Bluetooth and sends data to the Carly app, which you can download for free from your choice of app store.

The app then analyses the data and generates a detailed report, showing you any potential issues, errors, or faults with your car. The app also allows you to access and modify various settings and features on selected vehicles, such as comfort, lighting, or adding hidden functions. You can also view live data like speed, RPM, or fuel consumption and perform used car checks, emissions tests, or battery health checks.


What’s it like?

Carly is easy to use and offers a wealth of information and functionality. The installation process is straightforward, and the app guides you through the setup and usage steps. The user interface is clean and intuitive, with clear icons and menus.

The app provides explanations and instructions for each feature, and it also offers tips and recommendations from the Smart Mechanic feature, which acts as your in-pocket expert. Carly is suitable for both beginners and professionals, as it offers a range of features and options for different levels of expertise and needs.


Carly OBD Fault Code Reader In-depth

When opening the app for the first time, you’ll need to select your make and model and log in with your account. Plug in Carly to your OBD, then hit the Connect icon in the app. It will search, find, connect, and scan your car to ensure the model matches.

Then you can delve into the different options, whether that’s fault code reading, customising functions, reading live data, checking the history, the battery status…, and there’s lots more too!

Reading the ECU does take a while. For our BMW i3 it was a good 5-6 minutes – so bring a cuppa or something to do while you wait. You can speed up the communication time within the app settings, but that could cause issues if a certain ECU doesn’t respond in time. All Bluetooth readers are a little slow as they transfer data wirelessly; if you want speed, go for a fully blown fault code reader.


Health status warnings

Now, here’s where I disagree with how Carly presents your car’s health status.

Our little i3 came back as ‘Very Bad’, but as you can see, the main red issue is with the infotainment system. Having a fault with the infotainment system will never be a major or ‘very bad’ issue that stops your car from properly functioning.

The exact issue could be something well-known among i3 owners. A fault occurs when you put the rear heated screen on, and it interferes with the DAB aerial. No idea why. It must be something wiring-related, but it’s fairly common, and for me, well, anyone, that isn’t a ‘Very Bad’ health issue.

Am I ever going to be bothered to fix it? No. I never listen to DAB, and the heated rear window gets used less than five times yearly.

Or, it could just be a spurious error that Carly seems to through up with all BMW models, as I found this on an forum, and then this too.

I don’t think Carly should list anything under ‘Infotainment’ as a major health issue. Off the bat, it just makes you worry, and then it could make you spend money on repairing something that isn’t anything significant. Judging by the Google results on ‘B7F805’, it’s completely benign.

As with any fault code reader, you’ll likely be alarmed by the number of errors that come back upon a scan. But they’re often fairly benign or things you wouldn’t have even noticed.

Another of the ‘React immediately’ red warnings was for a rear door contact switch playing up – if this was to fully go, then yes, the car wouldn’t drive, but again, rear doors saying ‘open’ on the dash is another i3 quirk that comes and goes. So once again, you could spend money repairing something that isn’t entirely needed.

This error in question doesn’t even come up with any help when you Google it. I just know it’s in a sequence of errors related to that issue.


Fault code reports

Carly presents all the read codes in an easy-to-view list with a nice pie chart and overview. This can be saved as a PDF and stays in the ‘Digital Garage’ section.

You can also make coding changes (depending on the vehicle). To do this before, I relied on Bimmercode, so it’s nice to see that Carly has this function, too. There were five different ECUs that I could code, and these can change certain things like the welcome light duration, volume level on startup, display configuration, mirror dip for reverse, and literally hundreds more.

It’s a nice feature, but as with Bimmercode, you’ll likely make the change you need and never go in there again.

You can also run a Used Car Report, which will read the VIN numbers from different instruments around the car to ensure they match. It does the same with mileage to check for tampering.

There is an option to check the status of your 12V battery, but when trying it, I was asked to update Carly. It then ran through an update, but still didn’t work and just kept asking to be updated?!

Smart Mechanic is handy; it will tell you things to try to fix the issue. It doesn’t work for all faults, but it did come up with the DAB “fault”. You could equally just Google the error code yourself and find forums with info on for free…

Clearing codes was easy, but you do have to read them all first. I couldn’t find an option to just ‘clear codes’ from the get-go – which would be handy.

It’s worth pointing out that once you’ve cleared any fault codes on your car, drive it again for a few days or a week, then scan it again to see which ones come back. Any of the random ones should have gone, and you’ll just be left with recurring things that may need fixing.


How much does Carly OBD cost?

Carly is not a cheap device, requiring a subscription to access some of its features. The adapter costs £60 for most car brands or £79 for BMW. So, while the app is free to download, it offers different plans depending on the features you want to use.

The basic plan is free but only allows you to scan your car and view the errors. The full plan costs £9 per month or £59 per year, allowing you to access and customise all the features of your car.

The ‘all-brands’ plan costs £27 per month or £149 per year, allowing you to use Carly with any car brand.

Then the new ‘Smart Mechanic’ plan costs £36 per year, and it provides you with expert guidance and advice from the Smart Mechanic feature.

These subscription fees are recurring, and they can add up over time. For comparison, some of Carly’s competitors, such as the Windows based VCDS or ISTA, offer more features and functionality for a one-time payment.

For all this outlay, you could just buy a decent stand-alone fault code reader like the Mucar CDE900 Pro or the Topdon AritDiag 500 S – neither of those can code your vehicle, and they will require a one-time purchase to unlock certain features, but at least it isn’t yearly.


Carly OBD Fault Code Reader Conclusion

Carly can be a helpful car diagnostic tool which can potentially save you money if you DIY when it comes to fixes. It’s not perfect, as it could send you on a wild goose chase or inform you about faults that really don’t matter.

It also has limitations, such as needing a subscription to access some features, compatibility issues with some car models, and the risk of voiding your warranty if you modify certain settings via coding. However, these are minor drawbacks compared to the benefits of Carly if it ends up saving you an expensive trip to a workshop.


Owner / Editor of Carwitter


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