Besides a badly calibrated sensor the next most common reason for this issue is dust between the proximity sensor and the screen. For more info check this post.
Cleaning tips:
Clean the screen of your phone, especially the part where the proximity sensor is (See here).
If that is not enough open up the phone and clean it from the inside.
Remove the screen and blow onto the sensor and also wipe the sensor window in the screen assembly from the inside (I used a Q-tip for the window!).
Check the functionality of the Proximity Sensor with an app like Sensor Readout.
Workarounds
These should not be necessary anymore. If you cleaned and recalibrated (you may have to do it more than once) your proximity sensor and that didnât help you may want to contact support.
Disable the proximity sensor by putting a small piece of aluminium foil on it (picture). It makes the sensor feel that there is always light and the screen never turns off.
Then use the power button to switch the screen on and off.
Original Post:
Hi, I have my Fairphone 2 from Tuesday 5 January. I have a problem: when I make a call, the screen is totally black and it turns âonâ only when the people on the other side close the call. When I receive the call, the screen is ok. The problem itâs only when I make the call. So annoying!
Hi, I had this problem, too, and I am not sure if this has anything to do with the proximity sensor. I just rebooted my FP2 and now itâs working! The proximity sensor works like it should do.
If reboot doesnât work for you, there is at least a small workaround so you donât have to wait for the other caller to end the call: Go to Settings --> Accessibility and activate âPower button ends callsâ. Now you can use the Power button to end calls when you need to.
Thank you therob and AndreasLieser. Iâve followed the indications of AndreasLieser and now I can stop the calls using the power botton, but itâs not a good solution (I consider this solution as an emergency solution, because I want to see all the information on the screen). Iâve payed 525 euros for having a ânormalâ mobile phone
@Simone_Ricotta Have you tried the reboot? For me the reboot fixed it (for now)! And yes, the Power button workaround is just an emergency fix, you are rightâŠ
@AndreasLieser Yes, Iâve tried by rebooting for three times, without any success. In one attempt, the screen remains âonâ for only one-two seconds, just for a moment. What have I to do? Calling the support team? Asking for a substitution of the phone?
@Simone_Ricotta If the reboot did not fix it for you, I suggest opening a support ticket or file a bug. I think (hope) this is just a software problem, because after the reboot the phone function on my FP2 works as expected and the proximity sensor works fine, too. So there seems to be no hardware problem.
@therob@AndreasLieser Iâve solved the problem The problem was the tin plastic film on the screen. Iâve removed and everything now itâs ok. I think the film make some problems with the proximity sensor⊠Thanks for your attention!
Sometimes (Edit: almost all the time!!) the screen lock during telephone call does not turn off. I then have to remove the back cover and remove the battery in order to reboot the Fairphone 2. All other keys are dead. Is this a software problem or a hardware problem (e.g. the proximity sensor)?
Edit: it appears as if this problem only happens when the call is not answeredâŠ
Another Edit: After some tests Iâm just pretty sure that the settings for the proximity sensor are way too sensitive. I think there is just some dust blocking the sensor (on the upper left of the display) and that is enough to turn the screen offâŠ
Thanks for your reply. I think I should have written âif there is some dust (or a fingerprint) blocking the sensor, it is enough to turn off the screenâ. So, I was able to clean it by myself and I wanted to give a hint to other Fairphone 2 â users that might have the same problem. Sorry for the confusion. Anyways, the sensor might be a little bit to sensitive .
I moved our posts here as I think this is the same problem.
Maybe the proximity sensor is extra sensible during calls and therefore reacts even to fingerprints and screen protector foils.
One might argue that this over-sensitivity is a bug. What do you guys think? (Can you reproduce it by smearing the sensor or using a foil?)
it seems to be the same problem. Just a little smear (e.g. from âface greaseâ from a previous telephone call) or a fingerprint on the display at the position of the proximity sensor is enough to activate the lock screen. Even holding a finger 5cm away from the proximity sensor activates the lock screen. In the beginning, I thought it was a software bug since, in addition, I had an audio problem. But this was due to a microphone bug in the IPhone that I had used for testing; so this problem has been resolved.
However, Iâve just tested it with a few objects. A (transparent) plastic foil, a greasy finger print, a (transparent) plastic cover or glass are suitable for activating the lock screen with the sensor. Or just holding your finger a few centimeters above the sensor (even in the vicinity of bright light).
My solution for now is to keep the display very clean at all times.
My screen went black while talking when I used headphones/earplugs. even when i disconnected the headphones the screen stays off. Maybe there is a tiny short signal from the headphones port, so the fairphones assumes someone plugged headphones in.
In my case I simply could turn on the screen with the power button although I configured it to end calls.
I think in my case it works as it should. I can wake the screen with the power button and end the call by pressing a second time.
Maybe the problem could be fixed if the srceen turns back on when unplugging a headphone.
I actually donât have a Problem. I just wanted to point out, that I could turn on the screen with the powerbutton. And maybe there is a connection to the headphones jack
Hallo,
when i get called, the screen turns black, immediatly as i accept the call, (not because itâs close to my Head) and it is not possible turn it on, except the other person hangs up.
The problem was the tin plastic film on the screen. Iâve removed and everything now itâs ok. I think the film make some problems with the proximity sensor⊠Thanks for your attention! 
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