How To Fix Wi-Fi or Mobile Data Connection Issues on Samsung Galaxy S4 [Part 1]

Problem #7: AT&T Samsung Galaxy S4 not detecting 4G LTE/carrier network

My Samsung Galaxy S4 I337 (thru AT&T) is not picking up the data (4G LTE). Wi-Fi works fine, data IS turned on, if I take out SIM card it picks it up fine on any other phone, but when I have data on and Wi-Fi off on my Galaxy it will not connect to internet. I had AT&T look at it, they said I need new phone, and Samsung wants me to send it in to them. Have you seen this problem before? At first my phone was not reading SIM card all the time. Out of nowhere it would say “no SIM” until I reset or wiggled SIM card around. so I ordered a new SIM/SD card reader, 2 days before I switched hardware I noticed when it was reading SIM that it didn’t say 4G LTE on top. Now SIM works fine, but phone will not connect to carrier data. Please help? What internal part could cause this? — Benjamin

Solution: Hi Benjamin. Either the SIM card slot may be defective or the phone in general is having a hardware problem. It’s really difficult to pinpoint what might the exact problem be because we cannot physically check the device but if Samsung requested that it be sent for repair, please do so. Assuming that there’s no AT&T account or network problem, your best chance at getting a good working again is by getting it replaced or repaired.