What is the Secret Codes for Testing Mobile Screens?

Secret codes to test mobile hardware at the time of sale/purchase, or exchanging mobiles. With these secret codes you can test mobile screens of all companies for deadpixels, and touch problems.

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Secret Codes for Testing Mobile Screens

Many mobile manufacturers provide secret codes, also known as USSD codes, to help users and technicians test hardware components like screens, sensors, and more. Below are some common secret codes for different phone brands.

Important Screen Tests:

1. Samsung

Display Test: *#0*#
Hardware Information: *#7353#

2. Google Pixel

Display Test: No universal code. Use third-party apps or Developer Options for diagnostics.

3. Huawei

Hardware Test: *#*#2846579#*#*

4. LG

General Test Mode: 3845#*model# (replace "model" with your phone's model number, e.g., for LG G6: 3845#*860#)

5. Sony Xperia

Service Menu: *#*#7378423#*#*

6. OnePlus

Diagnostic Mode: *#808# or *#888#

7. Xiaomi

Hardware Test: *#*#6484#*#* or *#*#4636#*#*

8. Motorola

Device Information and Test Mode: *#*#4636#*#*

9. HTC

Test Mode: *#*#3424#*#*

10. Apple iPhone

Apple does not provide open secret codes like Android devices. Use third-party diagnostic apps or visit an Apple Service Center for official diagnostics.

How to Use These Codes

To use these codes, open your phone's dialer app and enter the code as if making a call. If the code is supported by your device, the diagnostic menu will appear.

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Dead Pixel TestInspect solid colors for dead, stuck, bright or dark pixels. Touch Screen TestCheck touch coverage, dragging continuity and dead zones. Keyboard TesterTest a full-size keyboard and confirm every key press. Mouse TesterTest buttons, wheel, movement, dragging and double-clicks. Audio TesterCheck speakers, stereo channels, tones and microphone input. Camera & WebcamTest built-in, USB, phone, tablet and compatible TV cameras. Microphone TesterView microphone levels, waveform, recording and playback. Pixel ExerciserExercise a suspected stuck-pixel area with changing colors. Gradient TestInspect gradients, tonal transitions and visible banding. Brightness & ContrastCheck black levels, white saturation and contrast separation. Screen Size TestView viewport, resolution, pixel ratio and display data. Text SharpnessInspect text rendering, browser scaling and clarity. Motion & GhostingObserve motion blur, ghosting and response behavior. Resolution & ScalingCheck screen resolution, CSS pixels and scaling. Device InformationReview screen, browser, hardware and platform information. Browser CapabilityCheck which browser APIs and hardware features are supported. Network TestCheck connection status, latency and estimated download speed. GPS & LocationTest browser geolocation, accuracy, altitude and speed. Sensor TesterTest orientation, motion, acceleration and rotation sensors. Multi-Touch TesterTrack multiple touch points, pinching and rotation gestures.Screen Color ToolsOpen exact full-screen color pages for pixel, uniformity and lighting checks.Response Time TestObserve ghosting, blur and pixel-transition behavior at several speeds.Stylus Drawing TestCheck pen, touch, pressure, tilt and drawing continuity in your browser.