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Tier C - Guided System Check Ready

Smartphone Proximity Sensor Troubleshooting & Diagnostic Guide

How to test the ear proximity sensor that blanks the screen during phone calls. Explains optical and ultrasonic proximity sensors, why web browsers cannot access them directly, and how to verify operation via phone dialers.

Mobile Phone Proximity Sensor Guide

Tier C • Guided System Check
Browser Proximity API Deprecation: The W3C Proximity Sensor API (UserProximityEvent) was removed from standard modern browsers due to privacy boundaries. Follow the manufacturer hardware test steps below.

Manufacturer Hardware Diagnostic Dialer Codes:

  • Samsung Galaxy: Open Phone dialer and dial *#0*# > Tap Sensor > Wave your hand over the top earpiece. The screen should turn bright green and vibrate when proximity is detected.
  • Xiaomi / Redmi: Open Phone dialer and dial *#*#6484#*#* > Select Proximity Sensor Test from the CIT hardware test menu.
  • Generic Android Call Test: Place a standard phone call (e.g. voicemail or automated service). Cover the top screen bezel near the earpiece with your palm. The screen should immediately shut off completely to prevent accidental cheek presses.

Common Causes of Proximity Sensor Failure:

  • Thick Screen Protectors: Glass protectors without an infrared cutout can refract the emitter's infrared beam, causing the phone to believe it is permanently near your ear.
  • Pocket Lint in Top Slit: Clean the micro-mesh earpiece speaker grill gently with a dry, soft-bristled brush.

How to use this test

  1. Clean the top glass bezel above the earpiece where the proximity sensor is situated.
  2. Test in a Phone Call: Dial a voicemail or automated number, place your hand over the top bezel, and confirm screen turns black.
  3. Android Hardware Diagnostic: Open phone dialer and enter '*#0*#' (Samsung) or manufacturer test code to access the Sensor test.
  4. Remove thick screen protectors that may block the infrared emitter.

How to understand your result

Looks good: Screen turns off reliably when upper bezel is covered during calls.

Troubleshooting: what to try next

  • Modern bezel-less phones use 'virtual proximity' which uses the ear speaker and accelerometer rather than an infrared sensor.

What this test cannot tell you

Web browsers block proximity sensor access for security; requires dialer diagnostic codes.

Frequently Asked Questions

EP
Tested & Reviewed by [REAL AUTHOR NAME - OWNER TO COMPLETE]
Last Reviewed: 2026-10-17 • Test Method: Authoritative mobile hardware diagnostic workflow and call test procedure • How We Test