Samsung Galaxy S4 — Wifi doesn't turn on

It's probably due to a file that your phone saves wifi info on, it's in root/data/misc/wifi, and it's called wpa_supplicant.conf., the previous rom may have written over it with data which is not usable by your current rom. You can just erase the file; the system will create a new one, although it means you'll lose all your known wifi passwords.

I meant root as in the root of the file system. There are several 'data/misc' folders, but this is in the main directory. It would be easy to delete/alter if you were rooted, obviously, but you might still be able to use adb to do it using 'pull' (adb is the Android Debug Bridge which enables your PC/Laptop to connect to the Android O/S). If you have adb set up then that's fine, if not there's an easy installer on this XDA thread.

Not sure as I'm not a Samsung user, but apparently you can. I can't be 100% sure that the file is what is causing the issue but in the majority of cases it is. Does wifi work after pulling your battery? It seems to be a temporary cure in some cases.

OK, just in case you hadn't tried that yet.

Hii There ... I HAve The Same Problem I Tried Using that method .. putting this on the dialer : *#0011# And Disactiving power save mode but it's just worked for few days after i did a factory reset a wipe data a wipe cache but nothing .. if i pull out the battery for some hours its will work for 2 to 3 min ... please help this problem is making me mad ... my phone is rooted anyway !! i just deleted those files u told her to delete and it's didnt work

Back up your Galaxy S4 then do a factory reset. When it reboots select your language. When it asks you to log in to an account like Samsung or google DO NOT and I repeat DO NOT login or setup these accounts, just simply tap next or skip. Then when it asks you to connect wifi, do a scan for your wifi then enter your access code for the wifi. Once connected go next and continue to the end. Then restore your files and check your wifi which should be now working. enjoy!!!!

Hi Everyone. I think I found out a method that works but you have to try it a few times... if you turn airplane mode on then pull the battery wait 5 seconds then hold the power button for a minute without the battery in the phone, after a minute put the battery back in and it should work

Tried everything i can find, even the solutions people here posted, nothing worked. Re-flashing the firmware worked fine for me. So, it seems that the only non-root method working is a firmware re-flash.