3G Data overrides Wifi

And when I log onto my (Windows) computer, I'm reminded of another RIDICULOUS issue of ATH.EXE using 100% of my CPU. ATH.EXE is apparently the listening service for "sync my iPhone over Wifi".

I've disabled "Sync my iPhone over wifi" numerous times, yet I'm still greeted with this issue.

So glad to find this discussion, I thought I was going crazy. I suddenly have been getting messages that I am going over my plan data usage!

I have an iPad2 with 3G that I hardly use. I usually keep the 3G turned off but lately, since I never use the 3G, I thought I would leave the 3G on for convenience when I do want to use it. Bad decision!

No problem until I started using YouTube for insomnia videos to help me get back to sleep - because it would all be on WiFi, I thought, since I was at home and ten feet from the router.

Now that I have read the posts here, I'm realizing that when the screen goes dark but the music etc keeps playing, the iPad must be switching over to 3G without me noticing. So the same must be true for my iPhone 4S. I assume I need to put it on airplane mode if I intend to use it to stream YouTube sleep aids.

Is the same thing true for using iTunes, that it will suddenly switch to 4G ?

Just realized that airplane mode is not the way to go! That turns off the WiFi!

You can turn the wifi back on when you activate Airplane mode.

Thanks, that did work. Learned something.

Glad that worked for you. My problem with the phones seemed to be fixed with an iOS update early this year. Is your iOS up to date? If the update fixes your problem, you won't need to turn wifi on and off to manage it.

I have this same problem but mine is compounded by the 'No SIM' message. While my iPhone 4 is asleep and connected to my home Airport network, the 'No SIM Card Installed' message wakes up the display and appears on the previously blank screen every 15 minutes followed shortly thereafter by a 'Network Lost' message. After a short 'search, the cellular network is then restored and everything seems to go back to normal.

This issue arises when the phone is sitting idle or when it is connected to a docking port on an iHome clock radio.

When I check my cell phone data, these events coincide with a 10KB download of data (equivalent to a simple email check) and they occur every 15 minutes.

This introduces an additional issue since my mail settings are to 'Fetch New Data' hourly.

So, it would seem that the problem is associated with a check every 15 minutes that the cellular network is still available (leading to the 'No SIM' display) followed by restoration of the cellular network.

What I can't figure out is why it then downloads internet data over 3G when the WiFi is booming in.

Can anyone help?

When wifi is on, but no internet service, mi 3G does not override wifi. I have to turn wife off to get on 3G Internet. Can 3G override wifi automatically when Internet is out

Yes, which my various iPhones have done beginning with the original iPhone in 2007 - the original was a non-3G phone but switched from wi-fi to EDGE and back again automatically.

Since I updated the phone about a year ago I had similar problems, but it took me a long time to realize and cost me a lot of money.

I work at home and am always connected to wifi. Usually I don't get/make any calls, and only text through watsapp. Yet I notice I use data off my data plan. The problem is it takes like 10 seconds for the phone to find the wifi (it's a strong connection). And when I get a new message it downloads it through 3G after I unlock the phone to reply.

This didn't happen with my old iphone 3GS.

I wonder how much money people are losing globally just because of this.