Samsung Secret Codes: 9 Safe Tests for Galaxy (2026)

My daily driver is a Tecno Spark 40 (HiOS, Android 15), so Samsung test menus reach me through other people’s phones: friends’ Galaxies, sellers’ tables. The routine below is the one I run on every Galaxy that lands in my hands: two safe routes, nine codes that still work, and the setting that silently blocks them.

Two Routes Into a Galaxy: Codes or Samsung Members

A Galaxy gives you two front doors for testing. Dialer codes are the fast door. You open the stock Phone app, type a code like *#0*#, and a hidden test menu appears on the spot. No install, no sign in, no waiting. Samsung Members is the official door. You open the Members app, tap Diagnostics on the Discover tab, tap Phone diagnostics, and run single tests or tap Test all at the bottom for the full pass.

Use codes when speed matters: a meetup table, a quick check on a friend’s phone, a fault you want to confirm in under a minute. Use Members when codes fail or when you want guided tests with plain pass and fail results. When a test fails, Members offers suggestions plus a View related FAQ link. Both routes test the same parts. Neither needs root, a computer, or a third party app.

Two limits to know up front. Members diagnostics only exist on Galaxy phones and tablets, so this guide is Galaxy only. And dialer codes are undocumented, which means any code can stop working after an update or on a carrier locked phone. A dead code proves nothing about your hardware. It says something about your software or your carrier, and this guide shows you which.

Do This First: Turn Off Auto Blocker

Years ago you typed a code and it just ran. That era ended with Auto Blocker, the Samsung security feature that blocks sideloading and suspicious USB activity. As a side effect it also stops most dialer codes. Android Authority confirmed it live in July 2026: with Auto Blocker on, the codes sit dead. With it off, every code in this guide runs on an unlocked Galaxy.

Turn it off before you test anything: open Settings, tap Security and privacy, turn off Auto Blocker, run your codes, then turn it back on when you finish.

One code ignores this whole dance. Dial *#06# and your IMEI appears with Auto Blocker on or off, on any Galaxy, every time. Memorise that difference: when *#06# shows but *#0*# does nothing, the blocker or the carrier is your problem, not the screen or the speaker.

On the newest software there is one more wrinkle. Recent One UI versions switch Auto Blocker back on by itself after you disable it, so a code that worked in the morning can fail in the afternoon. Recheck the toggle first whenever a code stops responding.

The Safe Codes That Still Work

Every code below is read only or test only, verified working on current Galaxy software by Android Authority’s July 2026 tests and Samsung community reports. Type each code into the stock Phone dialer exactly as shown. Most run the moment you type the last character.

Code	What it opens	When to use it
*#06#	IMEI display	Second hand check: match it to the box, receipt, and SIM tray
*#0*#	Full hardware test menu	Screen, touch, speaker, vibration, sensors, and cameras in one grid
*#0228#	Battery status	Live voltage and temperature when drain feels wrong
*#9900#	SysDump menu	Tap Delete dumpstat/logcat to clear old crash logs and free space
*#1234#	Firmware version	Read the AP, CP, and CSC lines to confirm the exact build and region software
*#0808#	USB settings	Switch between Charging and MTP when a PC refuses to see your files
*#2663#	Touchscreen firmware plus Wi-Fi version refresh	Tap TSP FW UPDATE when touch feels off; note the phone reboots on Wi-Fi refresh
*#0289#	Melody test	Quick speaker check without opening the full hardware menu
*#0283#	Audio loopback test	Speak into the mic and hear it back to confirm both ends of a call path

Two codes deserve a closer look. The *#9900# log clear freed 1.2 GB of stale logs in Android Authority’s test unit, which makes it the rare test menu item that also fixes a full storage warning. And *#1234# settles grey import arguments in seconds: the CSC line names the region software on the phone, so a Galaxy that updates late usually explains itself right there.

Notice what is missing from the table. No factory reset code, no region software changer, no wipe command of any kind. Those codes exist and they destroy data, some with zero confirmation, so they have no place in a testing guide. Every code above reads or tests and changes nothing, with one exception: the Delete dumpstat/logcat tap inside *#9900#, which deletes only disposable crash logs.

Inside the *#0*# Hardware Menu

Dial *#0*# for a grid of grey test buttons. Each isolates one part, and the full pass takes about five minutes.

Red, Green, Blue, and Black. Each fills the screen with one solid colour. Scan slowly for dead pixels, stuck pixels, tint patches, and banding, then drop brightness to minimum, where faint tint shows. Black exposes uneven tint patches along the edges.

Receiver and Vibration. Receiver fires the earpiece. A weak or crackling receiver is the fault sellers hope you miss, because everything else works fine around it. Vibration fires the haptic motor. A tired motor rattles through the frame instead of humming.

Mega cam and Front cam. Each opens a live preview. Point at text across the room and check focus lock on each rear lens, then flip to the front camera and look for dust under the lens glass. Shoot one frame per lens and pinch into the detail.

Sensor. Shows live readings from the accelerometer, gyroscope, proximity sensor, and the rest of the stack. Wave your hand over the top bezel and watch the proximity line flip. Tilt the phone and watch the accelerometer numbers move. Frozen numbers mean a dead sensor, and a dead proximity sensor keeps the screen on against your cheek during calls.

Touch. Lets you draw across the whole screen to find dead zones. Drag slowly along every edge and into each corner. If the line breaks in one spot, repeat the drag before you trust it: a dry finger fakes a failure once.

Speaker, Sub key, S Pen. Speaker plays audio through each speaker separately. On dual speaker Galaxies, cover the bottom speaker and confirm sound still comes from the earpiece. Sub key tests the buttons. S Pen appears only on stylus models. The grid is shared across the Galaxy range, so a missing test is normal, not a fault.

Two handling notes. Some tests run by themselves the moment you tap them, while others wait for your input, so give each button a few seconds before you call it broken. And no test shows an exit button, which confuses every first timer. Press the back gesture several times or use the volume keys to land back on the grid.

When a Code Does Nothing

A dead code has three usual causes. Walk them in order.

First, the blocker crept back. Open Settings > Security and privacy and look at Auto Blocker again. On newer One UI it can switch itself back on, and every code dies with it except *#06#. Flip it off and retry immediately.

Second, the carrier said no. Carrier locked Galaxies can answer codes with a connection problem error even with Auto Blocker fully off. That refusal comes from carrier firmware policy, not from Samsung, and no toggle overrules it. Android Authority hit this exact wall and confirmed the same codes run clean on an unlocked unit. Stop fighting the dialer and run Members diagnostics instead, which the carrier cannot block. Buying the phone? Treat a locked unit as a weaker deal and test everything through Members at the table.

Third, the code retired. Samsung drops individual codes on some models, regions, and updates without notice. When *#06# and Members both work but one test code stays dead, the phone is fine and the code is history on that build.

The fallback never fails you. Samsung Members > Diagnostics > Phone diagnostics > Test all covers screen, touch, speaker, mic, vibration, sensors, cameras, fingerprint, and battery with guided steps. It works on locked phones, new software, and models where every dialer code died. Slow, official, undefeated.

Verdict

Three facts decide how far these codes take you. First, the One UI 6 vs 7 split: on One UI 6 the Auto Blocker toggle stays off until you flip it back, while on One UI 7 and newer Samsung tightened background protection and the phone can switch it back on by itself (confirmed on One UI 8.5, which re-enables it after 30 minutes), so a code that ran yesterday can fail today and the toggle is always the first place to look. Second, the carrier warning: a carrier locked Galaxy can refuse codes with a connection problem error no matter what you toggle, because the carrier restricts access rather than Samsung, so buy unlocked where you can and test locked phones through Members instead. Third, the no harm promise: this guide carries no wipe codes, no region software changers, and no root steps. Every code here reads or tests and changes nothing, except the Delete dumpstat/logcat tap inside *#9900#, which clears only disposable crash logs.

Codes are the fast pass, not the full exam. Run the full new phone checklist next: sensors, storage, heat, and battery in depth, with each code matched to its manual test for days when the dialer refuses. Buying second hand? Take the five minute meetup routine to the table: the *#0*# grid and the IMEI check slot straight into its nine steps. Tell us in the comments which Galaxy you tested and which code caught the fault. Real reports teach the next reader what normal looks like.