[OnePlus 3 Questions & Answers] Luigi_4477:
Hello everyone!

Some basic info upfront:

The phone is completely stock(no root, etc) and on the latest available android update (9.0.6).

The phone was factory reset twice which didn’t fix anything.

Ambient temperature is 20°C

Behaviour:

Phone crashes related to heat:

- Whenever the phone screen turns black or the phone turns off due to a crash it is very warm/hot

-	The phone (sometimes) turns off when I connect it to the charging device while on low (<20%) battery

-	Battery temperature according to CPU-Z is normal (max 40-50°C) when charging and crashing

-	(External) heat causes the phone to turn off (exposure to sunlight, holding it in my hand for like 5 minutes while using light gaming app/camera – sometimes even lighter usage apps)

-	Phone turns off when used more heavily (e.g. frequent switching between apps)

-	Last time, the simple use of google maps and youtube caused the phone to go black eventhough it was positioned in front of the car AC and therefore temps should have been perfectly fine. When it crashed it was very warm to the hand tho

-	After a crash, the power button must be held for 10 - 20s to turn the device on again.

-	Sometimes it seems as if the phone might still be on, and only the screen is black (LED still blinking).

-	It seems as if holding the power butto first turns the device off and afterwards turns it on again

-	CPU-Z shows very high tempterature on the sensor “pm8994_tz”. It’s always at least 20°C warmer than the other sensors. Before a crash it shows between 90°C and 100°C while the other sensors are in the 50’s (not able to screenshot that :( )

-	The phone slows down and becomes choppy before crashing. If I notice this and stop using it right away for about 10 minutes I can sometimes prevent the phone from crashing.

[IMG="temperatures when phone doesnt cause issues / idle "]https://i.imgur.com/kb82177.jpg[/IMG]

Fingerprint reader not working:

-	Fingerprint reader doesn’t work anymore (have had this issue before. It somehow went away and is now back) the homebutton howerever is functioning

-	Also I think the last update for the OP3 made things worse. Fingerprint reader was working (with Andr. Pie - not 9.0.6 tho). Then I upgraded to 9.0.6. Fingerprint reader was still working. Then one crash. Since then the fingerprint reader is defect. I had times before when the FP-reader wasn’t working and the device stated that in red text. Now its just not working without any info from the phone.

- The *#808# sensor test says it's not a hardware malfunction. In the past the very same test also had already failed....

Android Data corruption:

-	Within the last 3 months my phone twice randomly bricked out of nowhere: When trying to use it it showed an android screen that said “Decryption unsuccessful” With the only option to factory reset the phone

[IMG="data corruption"]https://i.imgur.com/cUufDAk.png[/IMG]

All the issues have become more and more frequent over the last 1.5 years. At first only bothering every few month and now on a pretty frequent basis.

Other than that, on “normal” days the phone’s performance is perfectly fine.

I don’t know if this is related to the issues mentioned above but it somehow started after I’ve been to Vietnam: 4 Weeks of constant ambient temperatures of 40°C. In my pocket probably warmer and camera use on top of that.

Also I just plugged it into the Vietnamese power outlets with my european charger. I have no idea if different voltages or something like that might have caused issues

I started writing this down with the intention of just listing bullet points and it turned out as a pretty long text. However, when the phone doesn’t have issues (which is most of the time) it’s perfectly fine. That’s why I don’t wanna exchange the device. It’s basicly a well working phone – when its working….

Battery life is fine. 70% brings me through the day.

Questions:

- Hardware or software issue?

- faulty sensor?

- might older android version fix the problem?

Thanks for reading through this and giving your suggestions!

30.04.2020

UPDATE:

I downgraded back to Oos 5.0.8

- The phone feels snappier now.

- pm8994_tz temps are still above average

- I can't tell much about the heat-crash-stuff, since I'm not able to properly tax the system right now. However the device turned off twice during the setup process. Since then it's fine.

- I cannot setup a fingerprint because every security option requires me to enter the PIN. The devices says my PIN was wrong, although it's 100% correct. Funnily right now there isn't even a PIN set to unlock the device. So I'm stuck with the "swipe-to-unlock"-option. The statement about the wrong PIN also is an issue that sometimes occurred in the past out of nowhere.