If the steps in http://support.apple.com/kb/TS1559 don't resolve it your radio chip that provides WiFi and BlueTooth has probably failed. It's a weak point in the iPhone. The same chip is used in most other smartphones, and it has the same problem with all of them. But try that tip first, the try turning off Cellular Data and waiting 15 minutes, then try WiFi again. And if that doesn't resolve it sometimes the "hairdryer" trick will. Heat the phone from the back for a couple of minutes with a hair dryer.
Finally, you can take it to an Apple store and see if they have a solution. Sometimes, if you are only recently out of warranty, they will replace it anyway.
My daughter ( 14 years) hat the same problem with here IPhone 4S, no wifi after 6.1.3. her wifi and bluetooth where greyed and did not work anymore.
This week my wife and daughter where for a little vacation in Paris and went tthere to Apple store and told there here story, you don't believe she got a new IPhone 4S.
She was so very happy with her new Iphone.
Therefore I think, go to the Apple store and tell your story and maybe you get also a new IPhone.
I wish you all the best, I hope for you all that you get a new IPhone.
THANK YOU VERY MUCH APPLE STORE PARIS, FOR HELPING MY DAUGHTER
Uninstalling the upgrade would not fix the problem, as people who have done so by hacking the phone can testify. It is a hardware failure. Once hardware has failed it can't be fixed by software. The jury is out on whether the upgrade caused the hardware failure, but that doesn't change the fact that it is a hardware failure.
If you look a couple of posts above yours there is a report of this same failure that occurred months after upgrading. And if you search the forum's history you will find plenty of posts reporting this same problem with all releases of version 5, and all releases of version 4, and all releases of version 3. The radio chip is a weak point in the phone. The same chip is used in other smart phones, and the same problems have been reported with other brand phones.
I don't agree with that assessment, although I can see your point. We can't say for sure it's a hardware failure at this point. The fact that most phones fail right when the iOS upgrade is done (like mine) cannot be ignored. As someone else suggested, it could be that the new firmware is just less forgiving when it comes to interfacing with that particular piece of hardware, while the old code tolerated a higher level of fault.
There were also scattered reports of this problem when upgrading to 5.0. Not as many, but enough to be noticed. And either heating or freezing the phone fixes it for a lot of people with the problem. As I've never encountered heat sensitive software* in my 50 years of using computers that also points to hardware.
*Actually I have encountered heat sensitive software; in a few odd cases in multiprocessor embedded systems there is sometimes a "race" condition where 2 or more processes running at the same time will finish at different times based on the conductivity of components whose characteristics change with temperature. If the application isn't designed to accept either process finishing first it can cause an error condition. But that seems very unlikely in the single processor iPhone.
The software per se may not be "heat sensitive" but 1) It could be programmed to shut down the wi-fi at a lower temperature reading than the older version, therefore "graying out" and disabling the wi-fi feature at a stage where it wouldn't previously; or 2) It could be less tolerant of errors/faults when interfacing with the wi-fi hardware (dealing with hardware faults sometimes is a game of how many times you retry an operation before failing altogether; maybe the new iOS is just more impatient).
The fact that there were scattered reports of this problem caused by previous upgrades just adds to my hypothesis that this may not be a hardware issue at all. It looks like Apple has been tinkering with the sensors' readings and adjusting the software behavior at each new version, until they finally broke it for a lot of people. IMHO, the hardware has been working the same way all along, what's changed is just how the software interprets some readings.
While most of them are busy defining the techno aspects of this problem, as an end user, my issue is very simple. Buying a new phone shelling out another 140£ is definitely not wise given the life and track record of these complicated gadgets as it is more likely to fail again. I have chosen a poor man's solution which might sound odd and annoy few in this thread - I have changed my mobile service provider who used to offer just 500MB of data. I moved to another service provider who gives me unlimited data which helped me to overcome this problem. The root cause is Wifi not working , I have prepared myself to live without wifi , Long live apple!
Then you don't understand the issue. What is happening is that the hardware is ALREADY defective, when the phone was built. The iOS has nothing to do with whether or not the pre-existing hardware has a defect.
The iOS, when used with non-defective hardware, works just fine. When used with defective hardware, the defect in question becomes apparent.
The iOS is not defective. The device is defective.
It's like this: take a bottle that is supposed to have a 1 liter capacity. It's marked '1 liter'. But actually, it's defective, and is only 0.95 liters.
For the first month, you only ever put 0.90 liters in it. No problem. But one day, you put 0.97 liters in it.
The defective bottle overflows.
The non-defective bottles don't.
The liquid did not CAUSE the defect; it simply revealed its existence.
This IS a hardware issue. It's been documented by Apple. It's being addressed by Apple.
If the hardware has been working just fine under a previous iOS version, how can you call it defective? Flawed maybe, but functional. And obviously Apple had found a way to "silence" those flaws before and the devices worked until the new software was released.
No hardware is perfect, and software designers coding around flaws to prevent failure is quite common. Blaming it on the customer, or giving bad excuses like "the problem has been there all along", is just bad for the brand.
I guess we could go along with your theory that Apple sold millions of defective devices and (so far) hasn't done much to fix the issue, but I think it would be even worse for the company. Using your (rather weak) bottle analogy: the company knows that millions of its bottles can't hold more than 0.95 liters, so it sells them with 0.90 liter of soda instead (that's a bad start!!!). All of the sudden it tells its loyal customers to get 1 liter of its new soda flavor, knowing these customers are still using those flawed bottles. When the new soda overflows and customers begin to complain, the company basically tells them to... what? get a new bottle? Or throw away the part that didn't fit (in our case, the wi-fi portion)?
Either way, the customer is being cheated. *That* is the issue.
I upgraded to 6.1.3 approx two months ago. One thing I noticed is that the phone would be warmer than usual after streaming on YouTube. WiFi didn't go all at once. Little by little I would notice that it would loose connection more often until the other day when both WiFi and BlueTooth could no longer be enabled.
The phone is only a year and 2mos old and in execllent condition. I didn't expect it to have problems this soon.
Flawed and defective are the same thing. If my automobile's muffler doesn't work, the car can still drive. It's still defective & flawed, but operational.
No one is blaming the customer. Where do you get that?
Where are you getting your info that 'millions' of devices have this issue? Neither of my iPhones has this problem.
My bottle analogy was spot on. Apple didn't know the bottles were 'mislabeled'. As far as Apple knew, the 'bottles' were properly labeled to be able to handle 1.0 liters. So, when they filled the bottles with 0.9 liters and had no problem, they thought everything was fine. When they filled them with 0.97 liters, that is when they discovered the issue.
Customers that discover this hardware defect within their hardware warranty are receiving free replacements. How is that being 'cheated'?
What other product would you demand a replacement for a defect that was discovered AFTER the warranty expired? When the product is sold, Apple promises it will work properly for one year, with the option to purchase an additional year of warranty.
Did the product work properly during the warranty period?
If yes, then Apple has fulfilled it's promise.
If no, then Apple replaces the device for free.
Add in the fact that they offer a HUGE discount for out-of-warranty device replacement. Therefore, Apple is not saying to 'buy a new device at full price'. They're offering to replace a device that is NO LONGER COVERED under warranty at a substantial discount.
I don't see how you believe Apple is 'cheating' anyone.
The percentage of incidence where this hardware defect is actually occuring is far too low to warrant a recall, especially since there are no safety issues involved. A defective automobile can be a liability on the road. Your Wi-Fi not working on your iPhone isn't 'dangerous' in any sense of the word.
Also, Apple is replacing the devices for free under warranty. No need for a recall.