Android phones can last for years, but it's also true that over time they start to appear unusual battery, screen, sensor or connection failures which aren't always visible to the naked eye. And if the phone has been through several hands, relying solely on feel is a bit of a gamble.
To avoid surprises, the wisest thing to do is to use diagnostic apps and hardware verification toolsWith them, you can perform everything from a quick check before buying or selling a used mobile phone to advanced performance and component health tests. This guide includes a step-by-step diagnostic testYou have everything you need: exactly what they check, how to access hidden system diagnostics, and what the best free and professional Android apps are.
What are diagnostic tests used for on an Android device?
Diagnostic tests function as a Complete hardware MOT of your smartphoneThrough various tests, the app checks if the screen responds well, if the speakers sound as they should, if the battery maintains its charge, if the sensors report consistent values, or if there are connectivity problems.
This type of review is key when you're going to Buy or sell a used mobile phone on Wallapop, Milanuncios or similar sites.Because it allows you to demonstrate the device's condition with data. It's also very useful when you notice strange things like random restarts, audio cutouts, touch glitches, or a GPS that isn't quite working properly, and you want to know if the problem is hardware or software-related.
A good diagnosis can review from where the battery power actually goes and how much usable capacity remains (and how calibrate battery), including whether there are dead pixels on the panel, disconnected proximity sensors, problems with WiFi or Bluetooth, memory errors, or even replaced components that are not original from the manufacturer (not OEM).
In addition to detecting faults, many of these programs allow monitor the phone's performance and health on a daily basisThis is very interesting if you use your mobile phone extensively for work or play and want to anticipate potential serious failures.
Diagnostics without apps: secret codes and built-in tools
Before you go crazy looking for apps on Google Play, it's worth trying the diagnostic options provided by the system itself or the manufacturerMany mobile phones include hidden menus and pre-installed utilities that allow you to perform quite comprehensive tests without installing anything.
One of the best-known ways is to use the secret codes from the telephone dialerFor example, combinations like * # * # * # * # 4636 or the popular * # 0 * # (very typical in Samsung) they open internal panels with tests of screen, sensors, connectivity and battery.
In brands like Xiaomi There are specific codes such as * # * # * # * # 6484 o * # * # * # * # 64663 that activate a factory test mode with a lot of guided tests for buttons, cameras, vibration, sensors, and other physical components.
Other manufacturers integrate their own apps. Motorola, for example, includes the application Device HelpFrom this app, you can access diagnostics for battery, audio, cameras, connections, and touchscreen. Huawei is hiding this utility. HwMMITest, which is launched from Settings showing all system applications and allows you to run a guided hardware test when the battery is in a specific range.
In the Google Pixel There isn't a single diagnostic app that's entirely clear, and the secret codes don't always work the same way on all models. In these cases, users usually turn to official support and the Pixel help forums, where they can find self-help workflows and guided steps depending on the phone's problem.
These internal systems are perfect for a initial rapid screening for potential major flawsHowever, they have their drawbacks: the menus can be somewhat technical, some operators disable the codes, and in general, they don't generate easily shareable reports or provide as much detailed information as specialized solutions.
The best hardware diagnostic apps for Android
If you want to go a step further and have clear reports, guided tests, and highly detailed dataIt's recommended to install dedicated apps. Below you'll find a selection of the most comprehensive and popular tools for checking the hardware status and performance of your Android device.
TestM: fast and comprehensive diagnostics
TestME It has earned a place as one of the most accessible apps for any user. It offers quick or comprehensive tests grouped into six sections: screen, connectivity, sensors, hardware, sound and cameraIn a matter of minutes you can run up to 19 different tests for panel, colors and detect dead pixels, speakers, microphones, physical buttons, vibration or sensors.
The best part is that its approach is very practical: instead of just throwing out numbers and technical data, the app indicates which components pass the test and which ones failIt displays simple recommendations. Finally, it generates a report that you can save or share via messaging or email, ideal for a secondhand sale.
Phone Doctor Plus: Over 40 hardware and system tests
Phone Doctor Plus is a solution designed for those who want a Near-professional mobile phone check without needing to be a technicianThe app includes more than 40 types of diagnostic tests ranging from the screen and camera to memory, RAM, storage, sensors, and connectivity.
In addition to one-off tests, it allows a continuous monitoring of hardware, battery, memory, and storage spaceIt keeps a daily record of the battery's actual capacity and charging cycles, which helps to see how it degrades over time and know if it needs to be replaced.
You can also control data usage of the network to avoid surprises with the tariff, something especially useful if you usually use mobile data to the max and don't want to exceed the limit.
Thanks to these controls, the app becomes especially interesting if you suspect that your Your battery no longer performs as well as it used to, or you're experiencing intermittent hardware problems. that are not easily detected with other simpler tools.
Dr.Fone (Phone Check)
Dr.Fone is a suite known primarily for its ability to manage, transfer and retrieve data of mobile phones, but it includes a very powerful module of phone verification which acts as a hardware diagnostic tool and assesses the overall health of the device.
This section allows you to consult the details of battery capacity and temperature, RAM status, internal storage, charge cycles, and other key indicators from the system. Based on this data, Dr.Fone generates a very comprehensive report that is perfect for evaluating a mobile phone before selling it or trading it in.
This verification also helps you to detect performance bottlenecks, such as lack of available memory, overheating, or advanced battery degradation that is affecting daily life.
Device Info HW: Ultra-detailed technical specifications
Device Info HW is geared towards those who want to know exactly what components does your Android use and how do they behaveThe app attempts to identify each piece of hardware: LCD, touch panel, cameras, sensors, memory chip, internal flash, audio, NFC, charger, WiFi, Bluetooth, and battery.
On many devices it is capable of displaying the specific model of the panel, touchscreen and sensorsThis is very useful for technicians, ROM developers, or kernel developers. It even offers an online database to compare your phone with other models and see which drivers and chips they share.
Includes tests of Multitouch, screen color, download speed, sensor test And more. If your device is rooted, the app can read even more information, such as flash memory details or certain drivers that are restricted on recent devices.
The PRO version adds features such as HTML or PDF reports for sharing, permanent dark themes and an advanced list of internal devices (I2C, SPI, PMIC voltage regulators, partitions, codecs, USB OTG…). It is a particularly valued tool for detect non-original parts or hardware changes after repairs.
Device Info: Simple diagnostics with status information
Another very interesting alternative is Device Info (not to be confused with Device Info HW), an app that combines a a large amount of data about the phone's components with functional tests that are easy to run.
From a single interface, you can check the speaker, microphone, flashlight, display, light sensor, accelerometer, Bluetooth, Wi-Fi, fingerprint reader, volume, temperature, camera, and other key features. It also displays data on... memory, processor, installed sensors, screen size and resolution, IMEI and other system parameters.
One of its most interesting points is that it helps to visualize the battery health level and other wear dataThis helps in deciding whether it's worth repairing or changing your phone when battery life problems start.
Test Your Android / Test your Android
Test Your Android (often translated as “Test Your Android”) is a very user-friendly app designed for Perform quick checks to ensure all hardware is responding as it shouldIt allows you to run tests on the camera, speakers, fingerprint reader, multitouch screen, panel colors, etc.
It also incorporates specific tests for sensors such as compass, pressure, temperature, ambient light and many more. The idea is that in just a few steps you can confirm if any component is failing or underperforming.
Its strong point is that it is Very easy to use, even for someone who has no idea about technology.However, some versions display quite a few ads, and the pixel detection mode can be somewhat slow, plus it doesn't always generate exportable reports.
Android Hardware Info
Droid Hardware Info focuses on offering a clear X-ray of the device specificationsIt organizes data into tabs such as device, system, memory, camera, battery, and sensors, with specific information about SoC, resolution, screen size, storage, temperatures, and more.
One important advantage is that it lets you Export all the information to have a saved reportThis is very convenient if you repair mobile phones, compare models, or want to send the technician all your phone's data at once.
CPU-Z for Android
CPU-Z is a classic in the PC world that also has an Android version. Its main function is to offer Highly accurate data about the processor, memory, system, battery, and sensors Of the device.
You'll be able to see the CPU model, number of cores, frequencies, architecture, total RAM, device manufacturer, screen resolution, as well as battery status, level, temperature and voltageIt doesn't indicate in a user-friendly way whether "something is right or wrong," but rather presents raw data, making it more useful for users with a minimum of technical knowledge.
If you know how to interpret it, it's a fantastic tool for check if the specifications you were sold are real and to analyze the actual performance of the processor against other similar devices.
AIDA64: Complete hardware and system information
AIDA64 is another legendary app, inherited from the Windows world and adapted for Android. It specializes in displaying very detailed diagnostic information of hardware and softwareCPU and GPU detection, memory, system version, mobile and WiFi network, system directories, installed apps and much more.
Although it doesn't perform active testing as such (it's not a typical "screen test"), its strength is that it helps you to Verify that all the components listed are the ones the phone actually contains.Many users use it to unmask fake or manipulated mobile phones.
It also offers real-time measurements of CPU and GPU frequencies, temperatures, battery status and support for technologies such as Vulkan, OpenCL, CUDA, PCI and USB listings and sensor polling, which makes it highly valued by advanced users and developers.
DevCheck: real-time monitoring
DevCheck focuses on showing you how the mobile hardware is performing at any given momentIt clearly displays the use of CPU, GPU, memory, battery, network and other elements, with real-time graphs and statistics.
It allows you to see how many resources each app is consuming, component temperatures, and Technical details of the operating system, sensors, cameras and connectionsFor rooted users, it unlocks even more internal metrics.
If what interests you is Monitor for peak consumption, overheating, or potential bottlenecks While playing games or using demanding apps, it's one of the most highly recommended tools.
Benchmark apps: 3DMark, PCMark and others
In addition to purely diagnostic apps, there are the famous benchmark applicationsdesigned to objectively measure CPU and GPU power and, in some cases, battery life and storage speed.
Tools like 3DMark, PCMark, Geekbench, GFXBench, CPU-Z (as a benchmark), CPU X or AI Benchmark They run intensive tests and then assign a score that you can compare with other devices.
3DMark, for example, is designed to measuring graphics and CPU performance in 3D games and heavy workloadsshowing rankings and comparisons with a host of mobile phones and tablets, including iPhones and iPads. PCMark focuses more on daily tasks (browsing, editing documents, video and photos) and allows you to profile battery life with real-world usage scenarios.
Geekbench 5 offers CPU and GPU tests that measure both single-core and multi-core tasks, and also includes machine learning and augmented reality testsAI Benchmark focuses specifically on the performance of artificial intelligence (neural networks, image recognition, bokeh effect, etc.), with support for NPUs and dedicated accelerators in modern chips.
These apps are ideal for to find out if your Android is still performing at the expected level or whether upgrading to another model will be worthwhile in terms of raw power. However, it's important not to rely solely on benchmarks when buying a mobile phone: they should be combined with hardware health checks and real-world usage tests.
Professional diagnostic and certification software for businesses
When we talk about second-hand shops, refurbishers, and large mobile phone wholesalers, free apps fall short. In those cases, they resort to... professional certification and diagnostic software such as Phonecheckdesigned to process large batches of devices quickly and with traceability.
This type of solution is designed to automate diagnostics of dozens of control points on each device. Phonecheck, for example, boasts of performing tests on up to 80 aspects of the phone: WiFi connectivity, Bluetooth, GPS, sensors, screen, battery, cameras, physical buttons, vibration, and more.
One of its keys is the certification and generation of detailed reports for each device. These reports collect brand, model, IMEI number, production and sale dates, warranty status, whether the phone is reported as lost or stolen, or if it has outstanding debts or carrier blocks.
They also verify the authenticity of key components (screen, cameras, battery, motherboard, fingerprint button)Mark any previous repairs or non-original (non-OEM) parts. Since generic replacement parts are increasingly common in used mobile phones, having this information is essential for adjusting the price and avoiding claims.
Finally, these platforms incorporate features of Secure data erasure, audited and certified by standards such as ADISAto ensure that the phones are delivered completely clean of personal information before resale.
Hardware problems that these tests often uncover
When running full diagnostics, it is very common to find errors that the user had not noticed or that they attributed to the softwareAmong the most recurring problems, several patterns stand out.
One of the classics is the degraded or uncalibrated batterywith a real capacity far below the original. This causes the phone to run out of battery even when it still shows seemingly high percentages, or to suddenly shut down before reaching 0%.
Defects also often appear in the audio (microphones, speakers, call headset) or in the vibration motorSometimes due to impacts or very intensive use. Dedicated tests allow us to verify if each component responds with the appropriate volume, clarity, and pattern.
Touchscreens are quite typical dead pixels, areas without touch response, or panel miscalibrationwhich may go unnoticed if the entire surface is not tested with a specific test; and, if necessary, know how fixing a mobile phone screen.
Finally, it is not uncommon to find proximity sensors, gyroscope, accelerometer, or ambient light sensors that malfunction or report strange readingsas well as problems with WiFi, Bluetooth or GPS that affect the experience in online games, navigation or hands-free.
How to choose the best diagnostic app for your case
With so many tools available, the important thing is to choose one that suits you. your level of knowledge and the goal you are seekingWanting a report to sell a mobile phone is not the same as analyzing graphics power for games or designing custom kernels.
At the very least, make sure the app covers all key areas of hardwareBattery, screen, audio, cameras, sensors, memory, storage, wireless connectivity, and physical buttons. The best ones combine technical information with easy-to-use interactive tests.
La reliability and reputation of the application These also matter. Check ratings, update frequency, and developer support, especially in an Android environment where system versions change constantly and access to certain data is blocked for security reasons.
If you're going to use the results for sales, repairs, or appraisals, you'll be interested in the tool allowing you to Export or share reports in PDF, HTML, or other formats.And if you manage many devices, test automation and batch execution will save you a lot of time.
Regarding the interface, it's important that the app has clear instructions, organized menus, and guided testsIf you get lost among tabs full of incomprehensible numbers, you'll end up not really taking advantage of what it offers.
Who should use these diagnostic tools
The great thing about the Android ecosystem is that nowadays there are options for everyone: from the user who just wants to know if their battery is damaged to the store that refurbishes hundreds of mobile phones a month.
If you buy second-hand mobile phones, ideally you should ask the seller to Take a test with one of the apps mentioned and share the reportThis will allow you to objectively see the condition of the device before meeting in person or making the payment.
If you're selling your own phone, accompany the ad with a Recent diagnostic report boosts confidence and it helps you better justify the price, reducing the likelihood of returns or subsequent disputes.
For technicians, shops, and refurbishment businesses, the use of professional certification software It has almost become mandatory because it streamlines quality control, standardizes processes, and provides customer-facing documentation and guarantees.
And, of course, they are also very useful for curious users or technology enthusiasts who want to get the most out of their mobile phone, compare performance, monitor temperatures, or simply know in detail what parts their device has.
Having good diagnostic tools on hand and knowing how to interpret them makes the difference between going in blind when something goes wrong and being able to make decisions with data In your hand: from detecting a hardware problem in time to better negotiating the purchase or sale of a used Android, to checking if your mobile phone is still performing like the first day or is already asking for retirement.
