iPhone 17 Pro Max poor data connection compared to iPhone 15

My iPhone 17 Pro Max has poor data connection. Using the Field Test Mode (dialling *3001#12345#* in the phone app) reveals that the SINR values are between -30db and -20db which I understand is really bad. Compared to an iPhone 15, which has SINR of about +10db to +20db. So clearly there’s either a problem with my iPhone 17 Pro Max individual device, or the iPhone 17 Pro Max design in general.

I’ve tried getting the device replaced by Apple, which they have offered to do as they say it’s not right. But annoyingly they won’t send out the replacement device until days/weeks after receiving mine, and I need the phone every day to manage and monitor my health, which Apple Support care nothing about.

I’m wondering if my particular device is faulty, or whether all 17 Pro Max’s are equally bad.

Anybody else having a similar issue with data connection on the iPhone 17 Pro Max?

iPhone 17 Pro Max, iOS 26

Posted on Oct 15, 2025 12:32 PM

19 replies

JimR123 Author

Level 1

57 points

Oct 16, 2025 5:02 AM in response to Jeff Donald

Well one of the eSIMs is brand new as I only got it installed to compare with the first one after having the problem, so presumably that’s as good as being reprovisioned?

But honestly I’m not sure what reprovision actually means, especially when it’s not a physical SIM card.

Dec 2, 2025 3:08 PM in response to JimR123

I have had this for six months. First, I couldn't connect to the gas pump. Then, I couldn't scan the QR code at Chik-fil-a. Following that, I lost all GPS navigation on my phone. NONE of the map apps would work, despite all bars on my cell service. I finally figured out that rebooting the phone fixes it, so I have been doing that. I decided to just pay it off and order the new, lighter one. The weight has been bothering my hand, anyway.

Jeff Donald

Level 8

44,568 points

Oct 15, 2025 1:46 PM in response to JimR123

What country are you in? Why aren’t you testing 5G instead of LTE? You’re also testing different bands.

Dec 2, 2025 11:42 AM in response to Jeff Donald

iPhone 17 Pro Max poor data connection compared to iPhone 15