Comparison

Carly vs U

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Carly

This app allows car owners to diagnose issues, monitor live engine data, and perform maintenance tasks. It offers advanced features like coding hidden car functions and detecting mileage manipulation, helping users save on repairs and understand their vehicle's health.

Highlights
  • Read and clear fault codes from all ECUs
  • Monitor engine live data parameters
  • Step-by-step car repair guides
  • Perform car maintenance and reset service intervals
  • Check starter battery condition
  • Code and unlock hidden car features
  • Detect mileage manipulation
Features
Read full description

Carly is the most versatile OBD2 solution, offering diagnostics, engine live data, and guides for car repair and maintenance. It's helped over a million car owners to save up to $2,000 per year for car-related topics. Get the Carly app and the Carly Universal Scanner to access data through the OBD2 port of your car. Unleash your inner car hero with Carly! It works for Audi, BMW, Ford, Lexus, Mercedes, Mini, Opel, Porsche, Renault, Seat, Skoda, Toyota, VW, and almost all other car brands with an OBD2 port. As every car is unique, which specific Carly features are available will vary with every model, build year, hardware, and software. ———— BASIC FEATURES INCLUDED IN THE (FREE) BASIC PACKAGE Diagnostics (OBD), Live Data (OBD), and Emission Check (OBD) enable you to have control over the most important systems — engine and transmission. ADVANCED FEATURES INCLUDED IN THE PREMIUM PACKAGE (YEARLY LICENSE) • UNDERSTAND YOUR CAR'S HEALTH With Carly Diagnostics, you can read and clear fault codes from all built-in electronic control units (ECUs), including engine, transmission, ABS, airbag, and multimedia, keep track of your car’s health, gauge the severity of problems, and more. • POWERCHARGE YOUR REPAIR SKILLS Get expert repair guides for your specific issues to help you understand and fix the issues by yourself. • MONITOR ENGINE LIVE DATA Live parameters or live data can help you take the guesswork out of understanding what your car needs and narrow down the fault causes. • PERFORM CAR MAINTENANCE INDEPENDENT OF THE WORKSHOP The Carly Maintenance feature helps you step-by-step to service your car yourself, reset your service and keep track of your service intervals directly from your phone. • VIEW THE CONDITION OF YOUR BATTERY The Carly Battery Check function helps you monitor the status of your car's starter battery, which will help to increase your batterie lifetime. • CODE AND UNLOCK HIDDEN FEATURES Access hidden features set by the manufacturer and customize your car to fit your needs. This feature is only available on certain car brands/models, and the coding options vary between each control unit. • DETECT MILEAGE MANIPULATION Mileage manipulation is on the rise. Don’t get tricked when buying a used car — use Carly to perform a used car inspection before buying. ———— HOW IT WORKS Step 1: Check which features are available for your car model Step 2: Order your Carly Universal Scanner Step 3: Plug the scanner into the OBD2 port and log in on this app THE CARLY UNIVERSAL SCANNER — THE MOST ADVANCED OBD DEVICE The OBD2 device was designed to support almost all car brands with an OBD2 port and to enable advanced Carly features. The scanner comes with: • A lifetime warranty • Premium customer support Take the health of your car into your own hands! ———— You can purchase a subscription for an individual car brand or for all car brands. This is a yearly subscription. The subscription automatically renews for one year if not canceled at least 24 hours prior to the end of the current period. The subscription can be managed in your purchases and the automatic renewal can be deactivated there. Terms of Use: https://bit.ly/35Mxg5s Privacy Policy: https://bit.ly/35Rruze

About

U

This app allows users to diagnose vehicle issues using their smartphone and a compatible adapter. It provides access to check engine, ABS, and airbag codes, along with definitions and potential solutions. Users can also view live data and clear diagnostic trouble codes.

Highlights
  • Read and erase OBD II codes
  • View live vehicle data
  • ABS and Airbag code access
  • Automatic vehicle identification
  • Vehicle history log
  • Powertrain enhanced data
Read full description

U-Scan provides DIYers and Professional Technicians with access to vehicle diagnostics using their smartphone when paired to the available U-Scan vehicle adapter. Developed by the Global leader in DIY and professional diagnostic scan tools. U-Scan provides essential information to diagnose vehicles fast while saving money. •Get the probable solution to a check engine, ABS, or Airbag light. Simply connect the adapter to the vehicle and pair with your smartphone to start the diagnostic process. •QuickCheck™ - Review vehicle emissions status (I/M Monitors, Codes). •Read Codes - Read Global OBD II codes and display the definition. •Erase Codes - Erase Global OBD II codes. •AutoID™ - Automatically identifies most 2000 and newer vehicles for error proof diagnostics. •TrueLink™ - U-Scan will link to all 1996 and newer vehicles. •MyGarage™ - Library of all previous diagnosed vehicles. •Vehicle Activity Log – Detailed history of your U-Scan activities. •Screen shot sharing via Facebook and email •Optional App Enhancements - For access to more advanced diagnostic capabilities. Powertrain Enhanced Data •Get access to Powertrain codes and definitions related to the check engine light for most 1996 and newer GM, Ford, Chrysler, Honda, Hyundai, Nissan and Toyota vehicles via the manufacturer specific Read Codes Powertrain diagnostic commands. •Manufacturer specific code definitions for GM, Ford, Chrysler, Toyota, Honda, Nissan, Hyundai, Audi, BMW, Daewoo, Isuzu, Jaguar, Kia, Land Rover, Mazda, Mercedes Benz, Mitsubishi, Porsche, Saab, Subaru, Suzuki, Volkswagen, and Volvo. •Freeze Frame data - Details the conditions of the vehicle at the time the trouble code was set. •View and Graph LIVE Data - View RPMs, coolant temperature, oxygen sensor readings and more for a faster diagnosis. Over 300 sensor and data items are available as supported by vehicle. •Unlock CodeConnect™ and access the most likely cause of the check engine light. Get manufacturer specific powertrain DTC fixes. (If CodeConnect™ is owned.) • Enable manufacturer specific Erase Codes Powertrain diagnostic commands. Optional App Enhancements include: ABS Codes and Definitions - $5.99 per vehicle or $29.99 all manufacturers listed below •Get access to the ABS brake codes and definitions related to the ABS warning light for most 1996 and newer GM, Ford, Chrysler, Honda, Hyundai, Nissan and Toyota vehicles via the manufacturer specific Read Codes ABS diagnostic command. •Unlock CodeConnect™ ABS fixes and access the most likely cause of the ABS warning light (If CodeConnect™ is owned.) • Enable manufacturer specific Erase Codes ABS diagnostic command. Airbag Codes and Definitions - $7.99 per vehicle or $39.99 all manufacturers listed below •Get access to the Airbag codes and definitions related to the Airbag warning light for most 1996 and newer GM, Ford, Chrysler, Honda, Nissan and Toyota vehicles via the manufacturer specific Read Codes Airbag diagnostic commands. •Unlock CodeConnect™ Airbag fixes and access the most likely cause of the Airbag warning light (If CodeConnect™ is owned.) • Enable manufacturer specific Erase Codes Airbag diagnostic commands. CodeConnect™- First vehicle included free with purchase of adapter. Additional vehicles access $12.99 per vehicle or $39.99 all vehicles •Get the next step in diagnosing your vehicle. Access over 4.3 Million Fixes that tell you what is wrong with your vehicle with CodeConnect™. CodeConnect™ is a comprehensive database of over 4.3 million verified fixes for the trouble codes that cause the check engine and ABS warning lights to illuminate. These actual vehicle fixes have been reported and then verified by our team of ASE certified technicians. •Note: You must purchase Powertrain Enhanced Data and/or ABS Codes and Definitions to access respective CodeConnect coverage for manufacture specific Powertrain and ABS warning lights

Screenshots

Carly4 screens
U4 screens

Verdict

The call

The clearest difference is rating: Carly at 4.6 against U's 1.9. Carly also leads on update cadence (weekly vs every 4 months) and ratings volume (9.9K vs 125). U's advantage is iOS requirement (8.0 vs 16.0). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Carly sells 12 in-app purchases, starting at $11.99 per year and U sells 10 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Carly holds the better App Store score, 4.6 against 1.9. That said, the two scores are not equally well evidenced: Carly has 9.9K ratings behind it against 125, so its average is the more settled of the two. Written reviews point the same way: 29% of Carly's written reviews are positive against 11% of U's.

UpkeepUpdate frequency

Carly ships an update weekly, U every 4 months. The most recent releases landed on October 26, 2026 and October 23, 2026 respectively.

Scorecard5 real differences · 5 level
Carly versus U: the parameters behind the verdict, then further details
ParameterCarlyU
PriceFreeFree
Rating4.6 (9.9K ratings) — better1.9 (125 ratings)
Positive reviews29.3% of reviews — better10.9% of reviews
Number of ratings9.9K — better125
Update frequencyWeekly — betterEvery 4 months
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPadiPhone, iPod
Requires iOS16.08.0 — better
Further details — not scored
Size417 MB85 MB
Age rating4+4+
DeveloperCarly Solutions GmbH Co KGService Solutions US LLC

Customer experience

Carly

All ratings9,895 ratings
Positive91.7%
Neutral1.7%
Negative6.6%
Written reviews601 reviews
Positive29.3%
Neutral5.5%
Negative65.2%

U

All ratings125 ratings
Positive20.0%
Neutral2.4%
Negative77.6%
Written reviews92 reviews
Positive10.9%
Neutral4.3%
Negative84.8%

User reviews

Carly

From 9.9K App Store ratings

What we love

  • 👍 Great customer service
  • 🚀 Lots of functionality
  • 💡 Useful diagnostic and coding features
  • 🔒 Secure and reliable

Room to improve

  • 💰 Expensive subscription model
  • 🐛 Connectivity and compatibility issues
  • 🔍 Limited functionality for some vehicles
  • 📚 Confusing or lacking documentation

U

From 125 App Store ratings

What we love

  • ✅ Works well once successfully connected and configured
  • 📊 Provides useful diagnostic data and error code reading
  • 🔧 Helpful for identifying vehicle issues and troubleshooting
  • 📱 Good app functionality for tech-savvy users who understand setup
  • 💰 Reasonable price point for a diagnostic tool

Room to improve

  • 🔌 Severe Bluetooth connectivity issues - frequent disconnections
  • 🔄 Extremely difficult and unreliable pairing process
  • ⚠️ False 'vehicle in motion' errors when car is stationary
  • 🚫 Cannot use live data while vehicle is moving (post-update restriction)
  • 🐛 Firmware updates frequently fail or brick the device

Bugs and requests

Carly

Reported bugs

3 issues
  • App crashes or freezes
  • Adapter not working as expected
  • Inaccurate or misleading diagnostic information

Requested features

4 requests
  • More vehicle support
  • Improved user interface
  • Offline functionality
  • Easier subscription management

U

Reported bugs

15 issues
  • Bluetooth connection drops frequently and won't reconnect
  • App fails to recognize connected Bluetooth device
  • Firmware update process freezes and becomes unresponsive
  • False motion detection errors preventing app operation
  • VIN entry not working or not submitting to garage
Show 10 more
  • App crashes during scanning or data retrieval
  • Device won't pair after firmware update
  • App takes 2+ minutes to recognize connected device
  • Bluetooth pairing requires manual connection in settings
  • Vehicle module detection fails or shows incorrect modules
  • App forces landscape mode without option to change
  • Live data display limited to only two screens of information
  • App won't function without mandatory vehicle garage entry
  • Connection errors persist despite correct Bluetooth pairing
  • App becomes unresponsive during update process

Requested features

10 requests
  • Enable live data monitoring while vehicle is in motion
  • Improve Bluetooth auto-detection and automatic connection
  • Add support for Australian vehicle models (Holden, Ford)
  • Expand vehicle compatibility beyond 2013 models
  • Implement dark mode for app interface
Show 5 more
  • Add customizable data display options
  • Improve app responsiveness and reduce connection delay
  • Provide comprehensive manual and troubleshooting guides
  • Add support for more vehicle modules (ABS, airbag, transmission)
  • Implement automatic firmware updates without user intervention

In-app purchases

12 purchases

Carly

Subscriptions12
  • Smart Mechanic$11.991 Year
  • Toyota$21.991 Year
  • Mercedes$28.991 Year
Show 9 more
  • Smart Mechanic$35.991 Year
  • Volkswagen, Audi, Seat, Skoda$53.991 Year
  • Carly for BMW Full-Version$59.991 Year
  • BMW and Mini$63.991 Year
  • All Brands Upgrade6 Months trial$78.991 Year
  • All Brands$82.991 Year
  • VW/Audi/Seat/Skoda + Mechanic$89.991 Year
  • BMW and Mini + Smart Mechanic$99.991 Year
  • All Brands + Smart Mechanic$118.991 Year
10 purchases

U

One-time10
  • ABS Codes and definitions for Single Vehicle$5.99
  • ABS Code Vehicle 2$5.99
  • Live Data and Manufacturer Specific Codes Vehicle 1$7.99
Show 7 more
  • Airbag codes and definitions for vehicle 1$7.99
  • CodeConnect Repair Solutions for a Vehicle$12.99
  • Live Data and Manufacturer Specific Codes All Makes$15.99
  • CodeConnect Repair Solutions 1 Vehicle Upgrade to All$27.99
  • ABS Codes and Definitions All Vehicles$29.99
  • CodeConnect Repair Solutions All Vehicles$39.99
  • Airbag Codes and Definitions for All Makes$39.99

Questions

Is Carly free?
Carly is free to download, with in-app purchases available.
Is U free?
U is free to download, with in-app purchases available.
Which has better reviews, Carly or U?
Carly is rated higher. Carly averages 4.6 out of 5 from 9.9K ratings, while U averages 1.9 from 125 ratings.
Do Carly or U have ads?
Neither Carly nor U shows ads.
Which is updated more often, Carly or U?
Carly ships an update weekly, and U every 4 months. Most recently, Carly was updated on October 26, 2026 and U on October 23, 2026.

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