If your Samsung Galaxy is acting strangely, you can test hardware using the built-in diagnostics suite. Go to Settings > Device care > Diagnostics > Phone diagnostics to run individual tests or tap Test all. Available on Galaxy devices with Android 12 or later, the tool checks touch screen, cameras, microphones, speakers, buttons, sensors, Wi-Fi, mobile network, Bluetooth, SIM, NFC, USB, charging, and fingerprint reader.

Models with S Pen or wireless charging include extra checks. Some tests require user interaction, like covering the front camera for proximity or listening for audio playback. Results include battery status rated as Normal, Weak, or Bad, with Weak indicating reduced efficiency and Bad signaling significant degradation needing service.

Passing diagnostics does not guarantee original speed, as tests verify function, not performance benchmarks. Slowdowns may stem from outdated software, background apps, low storage, or system errors. Repeated failures or a Bad battery suggest repair.

Samsung’s Maintenance mode protects data during servicing. I tested the full suite on a Samsung Galaxy S26 Ultra, which included 22 checks. This is a hardware health check, not a speed test.