Quectel 4G Module Internet Connection Troubleshooting Guide

About this manual

This document provides a step-by-step guide for troubleshooting 4G module internet connection issues without requiring log analysis. It begins by using the AT+CEREG command to determine the network registration status and potential causes such as signal strength or network rejection. It also checks SIM card recognition using AT+CPIN? and verifies physical antenna connections. This manual is written in Chinese.

What's inside

• AT+CEREG Network Status
• SIM Card Recognition
• Antenna Connection
• Function Mode Check
• Network Search Mode
• Band Configuration
• Network Scan Mode
• Signal Quality Check
• Private Network Configuration
• Log Analysis

Frequently asked questions

What does the return value +CEREG: 0,2 indicate?

It represents searching for a network, which is generally due to signal reasons.

What does the return value +CEREG: 0,3 indicate?

It represents network registration being rejected, possibly due to the SIM card or network side issues.

What does the return value +CEREG: 0,4 indicate?

It represents an unknown issue, suggesting the module might be registered on another network standard.

What does a return value of 0 for AT+CFUN? indicate?

It indicates that the radio frequency and (U)SIM card are not working.