Touch problems on a Galaxy S20 include a screen that ignores taps, registers phantom touches, or flickers, and the cause is split between software and hardware. Start by removing the protector and case and cleaning the screen, because the S20's curved edges and a thick protector can reduce sensitivity at the sides. Check that Touch sensitivity is on in Settings, Display, which is meant for screen protectors. Restart the phone, and test in Safe mode: if the screen works normally there, an app is at fault and you remove the latest installs. Phantom touches while charging point at a poor charger or a wet port.
A green or pink line down the display, or a section that never responds, is a hardware fault of the AMOLED panel that appears on some S20 phones and needs service. If the screen misbehaves only when the phone is warm, heat is involved and the cure is cooling the phone; if it misbehaves while charging, test another charger and cable. Samsung Members has a Touch screen diagnostic that draws a grid so that you can see exactly which areas fail. A screen that is fine in the morning and erratic later may be warming up, so test it again after the phone has cooled.
Differential
Likely causes of “Samsung Galaxy S20 family screen or touch input is not working correctly”, and how to tell them apart
- 1
A protector or case
What separates it Touch is patchy at the edges
How to confirm Remove it and test; turn on Touch sensitivity
- 2
Dirt or moisture
What separates it Random taps
How to confirm Wipe and dry the screen
- 3
A software glitch
What separates it The screen froze
How to confirm Restart
- 4
An installed app
What separates it The screen works in Safe mode
How to confirm Uninstall recent apps
- 5
A panel fault
What separates it Lines or a dead area
How to confirm Contact Samsung
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the whole screen or an area fails
- Whether a protector is fitted
- Whether it works in Safe mode
- Whether lines appear
Try in this order
0 of 10 completedRemove the case and protector
ReversibleTest the bare screen.
Turn on Touch sensitivity
ReversibleSettings, Display.
Clean and dry the screen
ReversibleWith a soft cloth.
Restart the phone
ReversibleHold power.
Test in Safe mode
ReversibleHold power, touch and hold Power off.
Contact Samsung for lines
ReversibleA panel fault needs service.
Run the touch diagnostic
ReversibleSamsung Members, Phone diagnostics, Touch screen, then drag a finger across the grid to see dead zones.
Test while charging and unplugged
ReversibleCheck whether the problem appears only with a charger connected.
Take the protector off completely
ReversiblePeel off any film so that you test the glass itself.
Test when the phone is cool
ReversibleLet the phone sit off for twenty minutes and test the screen again.
Model-specific
What is true of this model and not of its siblings
- Curved edges
- The S20's edges are sensitive to protectors.
- Lines
- Colored lines are a panel fault, not software.
- Dead zones
- The grid test shows an exact area, which helps a repair desk.
- Charger noise
- A poor charger can cause phantom touches.
- Panel faults
- Colored lines on the display are a hardware fault.
- Heat link
- Heat can make a failing panel misbehave.
Stop boundary
When this stops being a self-service repair
- !If lines appear or a section is dead, contact Samsung
- !If the screen fails in Safe mode, book service
- !Do not use a cracked screen
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why does my S20 screen not respond?+
A protector, dirt, a software fault or a panel issue.
What is Touch sensitivity?+
A setting for screen protectors.
Why do I see a green line?+
A panel fault.
Does Safe mode erase anything?+
No.
How do I test my touch screen?+
Use the Samsung Members touch diagnostic.
Why does it tap by itself?+
Moisture, a bad charger or a panel fault.
Does heat affect touch?+
It can make a failing panel worse.