Cellular data not working on my iPhone 12 Pro after iOS 18.3.1 update

After the update my cellular data doesn’t work and I lose cell bars to how can I fix this

18.3.1 battery issue is a BIG deal!

"IOS 18.3.1 iPhone update horrors: After updating to iOS 18.3.1 my phone does not have the ability to use cell data service. The battery drains extremely fast now as well."

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Troubleshooting iPhone Battery Draining:

I. Report this to Apple:

Do your Part: Provide Apple with feedback on this, letting them know about this issue.  Apple may not get back to you directly, but the more feedback they receive on this, the more they will know what is occurring, and what bug fixes to include in updates to come.

1. Go Here: Feedback - iPhone - Apple
2. Select: "Bug Report" for the "Feedback Type"
3. Comment: that this all began after installing an update. Include the URL of this post
4. Proceed from there as necessary

II. Tips on this:

Unfortunately, there is no way to determine when nor why the Battery Health decreased.

A. Battery Drain Info:

The iPhone battery will drain, unless it is plugged in and charging. With lots installed, the charge would be slower. As for how fast it would drain the battery, that would depend on the battery health and the volume (sound) you use.

1. Go Here: iPhone Battery and Performance - Apple Support
2. Scroll Down: to "Your battery's maximum capacity"

B.. Troubleshooting the Battery:

• iPhone Battery and Performance - Apple Support

• Charge and Monitor the iPhone Battery - Apple Support

• About the Battery Usage on your iPhone - Apple Support

• About Optimized Battery Charging on your iPhone - Apple Support

• If you see "Your iPhone Battery may Need to be Serviced" - Apple Support

• Use Low Power Mode to Save Battery Life on your iPhone - Apple Support

“Thank you for the link I was trying to find the report bugs link. Usually it shows up on my MacBook lol”

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You are welcome. Apple is not out there to scam you —it’s just a mishap or configuration during the update install.

I have the same issue called Apple support they wanted to me to restart do diagnostics test then reset blah blah. I said no. Every time I restart it fixes it for two hours then lose cell service again and it’s not Verizon as my daughter in my house has cell and has iPhone as well and didn’t do update. Smh. I reported the bug but it’s crazy to me they didn’t advise me of this being an Apple issue at all til I mentioned this thread

GentlemanBastrd wrote:

After updating to iOS 18.3.1 my phone does not have the ability to use cell data service. The battery drains extremely fast now as well.

Does Apple purposely put out incomplete updates and then does nothing to get them fixed in a timely or hurried manner? I have tried every fix I have found but to no avail. I figured after a horrible update people would get fired but it seems they just keep getting put back on them lol. Why does this happen with a 1000 dollar phone?? I’m really thinking about leaving apple and going android against no more MacBook, phones, iPads nothing. I’m actually tired lol

There is no Apple here in these user to user technical forum.

What does tried all fix include?

What did your phone carrier say when you contacted them about your cellular data issue?

“18.3.1 battery issue is a BIG deal!”

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To all participants and those affected by this…

Report this to Apple:

Do your Part: Provide Apple with feedback on this, letting them know about this issue.  Apple may not get back to you directly, but the more feedback they receive on this, the more they will know what is occurring, and what bug fixes to include in updates to come. Apple will know nothing of your occurrence, if you don’t report it to them.

1. Go Here: Feedback - iPhone - Apple
2. Select: "Bug Report" for the "Feedback Type"
3. Comment: that this all began after installing an update. Include the URL of this post
4. Proceed from there as necessary

Not sure if people here still have this issue.

My girl has the same and I checked and tested the following:

Go to Settings -> Mobile network/cellular

Open -> Network selection and disable automatically.

Select the name of the provider you are using.

Example for people in the Netherlands; KPN, Odido, Vodafone etc.

Enable flight mode for 1 minute and disable it.

Please check if data and cellular is now working.

If not..

Than go back Settings -> Mobile network/cellular -> Cellular Data Options and check the APN name.

Google the APN namens of the provider you are using and try different options (old and new ones).

Restart the iPhone and test it again.

"IOS 18.3.1 iPhone update horrors: After updating to iOS 18.3.1 my phone does not have the ability to use cell data service. The battery drains extremely fast now as well."

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Troubleshooting Cellular:

A. "No Service":

Is "No Service" shown on the top-left corner of your screen? If so, go here to fix that: If you See No Service or Searching on your iPhone or iPad - Apple Support

B. No SIM":

Is "No SIM" shown on the top-left corner of your screen? If so, go here to fix that: If you See 'invalid SIM' or 'no SIM' on your iPhone or iPad - Apple Support

C. Contact your Carrier:

Having issues with Cellular, contact your Carrier, asking them to configure this to the correct settings. They configure all of this in the SIM card.

I have experienced the same issues since (at least) 18.3 on iPhone 12 mini.

Very rarely I could temporary get a cell connection after many network resets, airplane mode, sim inserts, etc. my carrier also replaced my sim with no luck.

Apple Store was no help, other than offering a $400 “repair” for a refurbished 12 mini.

Personally, I think it is a modem firmware issue.

[Edited by Moderator]

My iPhone 12 had the same problem after I updated to iOS 18.3.1.

I’m with AT&T, and the dropping cellular data made me crazy for about two weeks.

If anyone else is bothered by the same issue, you might want to swing by an AT&T store.

The guy there converted my SIM to an eSIM and did some setup, and now it’s working again.

Really appreciate the help from that guy!