iPhone 4S losing network - no signal

earlier which sim u were using was it was of vodaphone i m facing same problem n apple supporter ask me to replace the i phone

To let know Apple that this network problem just started with my 4S as well. About one month after purchase. I am base in Thailand, with Thai carrier. Got the phone in Singapore.

Hello guys, do u know apple removed the option of manually selecting between 2g and 3G network (unlike i4)? So now iPhone will itself decide which carrier to choose based upon some algorithm, so if u r with a carrier which doesn't have good 3G coverage at ur place then fone will keep on selecting between gsm and umts!!!

its been almost about 3 weeks since i updated to ios 5.0.1 ( 9A406 )

and that happened because i was really frustrated and angry about losing signal, no service, sim failure, no sim and lots of problems.

at the begining, everything was working perfectly, no errors and i was able to send / recieve messages make calls and never lost the network or missed a call.

but i noticed that whenever im in a low coverage area, my device showed the no service message and it took about 10 min to get the signal back.

but i found a way to force it to catch a signal much faster and that is by calling myself from the same number.

but 3 days ago, i waked u having the no sim error ! and for a second, it felt really bad, then the situation occured again after 6 hours, then i waked up in the last 2 days having the same problem and nothing fixed it other than restarting my device or reseting network settings. and the frequency of losing the signal increased dramaticly.

i think 5.0.1 ( 9A406 ) was a temporary fix and it was aimed to calm us or make us think that our problem is solved what gives apple extra time to find a solution ( although i think that they never will ).

you are the real man, i was having same problem in my iphone 4 with iOS 5.0.1

now i haven't done anything except to change Settings --> Carrier --> Automatic ( turn it off and select your network manually )

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and my problem is solved...many thanks 🙂

hello eveybody. i have the iphone 4s since almost 3 months and since day 1 problems started, losing network, no service, sim failure and battery draining. and since day 1 i was trying to find a fix. after contacting may carrier they told me that it is a software-hardware incompatibilty between the 4s ios and the sim card and the network signal frequency of the carrier company. and i had to wait untill the new sim cards are produced. Meanwhile i was using another carrier company sim cards and my iphone worked much better. after that apple released ios 5.0.1 (9A406) so i returned back to my old carrier sim card and it worked good but some problems remained. 3 weaks ago my carrier company delivered the new sim cards although my phone was working fine. but for curiosity purpose, i tried to install ios 5.0.1 (9A405) again using the new delivered sim card, and no problems showed and i was able to call and text anytime. so i discovered that the no service and the no sim errors are generated due to sim-ios incompatibilty. but the battery draining and the latency in recovering the network after moving from a low coverage area to a good coverage area remained, and everytime i went into the elevator, underground, or any place with low coverage area, i lose the network and no service appeared "wich is normal" but if i go back to a high coverage area, the no service message remained for almost 10 minutes minimum "wich is completely not normal". more investigation about this problem and contacting apple bug reporting service and lots of trials, i discovered that this case is the main issue and it is behind the battery draining. Simply it was the diagnostic and usage reporting. whenever u enter a low coverage area, your phone loses network, causing an error generation, so your iphone tries to send this error message to apple server while you are without connection, it tries again and again and again without success, so the os shuts down the process of sending the error report and the network reception shuts down " you can simply monitor the procedure by installing the configuration utility from apple website " and monitor the configuration log where you can see the process happening untill shutting down the carrier reception retrievel function. so the solution and only solution was to turn off the diagnostic and usage sendind data automaticly. and after doing that, battery and no service error completely fixed.

SO TRUST ME THIS IS THE SOLUTION AND FOR BEST RESULTS

- ORDER LATEST SIM MODEL FROM UR CARRIER

- INSTALL IOS 5.0.1 (9A406)

- REMOVE SIM PIN

- TURN OFF DIAGNOSTIC AND USAGE AUTOMATIC SEND

- USE YOU PHONE UNTILL BATTERY DRAINS AND SHUT DOWN THEN RECHARGE TO 100% "to refresh it and calibrate it"

Wish u good luck and let me know your feedbacks.

I had similar problem when I bought my Iphone 4s in Feb 2012 in India. I followed the below procedure and it started working fine without any problem.

IPhone 4S purchased any where have lot of problems while using in India particularly..Airtel Network. I have struggled for 2 weeks with Airtel micro SIM..finally solved the problem. Just down load itunes(latest version) in your computer. Connect I-Phone 4s to the computer.Open i tunes.Your i-phone name will appear on the left side of itunes menu. Click on that.Right side option for Version is available.Under Version..there are 2 options..update and restore. Click on restore..It took me 1 hour (my internet speed was 2 mbps) to upload latest factory setting with unlock option.While download never disconnect your i-phone or internet.If in between any interruption then download starts from the begginning.Once restore setting your i-phone 4s works without any problem.

I had the same problem of the iPhone 4S continually searching for a signal, and wearing down the battery quickly in the process. I had the phone 3 months no problem then all of a sudden it just started (as of May 2012). My current OS version is 5.1.1 and carrier is Verizon 12.0

I followed the directions to reset network settings as described at the Apple support site here: http://www.apple.com/support/iphone/assistant/calls/#section_2

When it reset, I originally got a message pop up that said "could not activate cellular network", so I thought well that did not help! But then about a minute later I got my expected full signal strength! So I don't think it was the carrier , hoping I don't need to go through this again.

I hope this is useful to someone.

Hi, I have just been through 2 days of researching and trouble shooting this low signal/no service problem which just occurred... very frustrating.

My phone:

Iphone 4S factory unlocked

5.1.1

MD234X

Carrier:

3 mobile UK

After reading many posts on the issue this is what didn't work and what did.

Didn't Work:

Reset network settings

Re-calibrate Battery

Restore phone in itunes to original factory settings without sim

Disabling all data functions, resetting network settings and then and manually setting network

Did Work:

Before trying a brand new sim from 3 I thought I would try my sim in a different iphone 4S (also unlocked). So I swapped sim cards (3 mobile and a O2 sim) between phones and checked the signal strength with the Field Test mode. The signal strength was showing around -90 on both which is OK. (it has been as bad as -130 or no service) I then swapped the sim cards back again and my phone is working normally again! I guess putting in a different carrier sim somehow reset some settings that the restore couldn't.. go figure!! Atleast it is working now so I am a happy camper 🙂

BTW Field Test mode *3001#12345#* Call

Just to follow up. I recently started using bluetooth (hands free car kit) with this phone around when the no service issue started. After fixing the phone and using bluetooth again the problem returned. I think somehow using the phone through bluetooth is corrupting my carrier settings and causing the problem, so I shall wait for future software updates before trying the bluetooth handsfree again.