How to Enable Qualcomm Diagnostic Mode on any Android Phone

Qualcomm Diagnostic Mode or Diag Mode is useful for changing the IMEI or repair baseband on your phone using QPST, WriteDualIMEI and other tools. If you are facing “cannot find DIAG COM Port” or similar error, then follow the steps listed in this tutorial to enable Qualcomm Diagnostic Mode or activate Diag Mode.

To fix IMEI or repair baseband it is required that your device have proper root permissions. So, make sure your device is rooted and have proper Root permissions.

Some phones support activating Diag mode using the secret code. Follow the below steps to see if this method works on your device.

Method 1: Enable Diag Mode using Secret Code

Open phone dialer app on your device and type #*#717717#*#*. This should enable Diag Mode and fix cannot find DIAG COM Port error. If nothing happens then try other methods listed below.

Method 2: Activate Diag Mode using ADB

In this method, we will make use of ADB commands to enable Diag Mode. It requires that you have rooted your device and have proper root permissions.

Step 1: Install ADB and Fastboot drivers on your PC from here. Also, make sure to install the suitable Android USB Driver for your device model.

Step 2: Enable USB Debugging on your device from Settings > Developer Options. If Developer Options are missing, enable them from Settings > About Phone and tap on Build Number for about 7-10 times.

Step 3: Connect your device to PC and enter the below commands.

adb devices

This command lists the devices connected to PC with USB Debugging enabled. If your device doesn’t show up in the list, then make sure you have installed ADB, Fastboot and USB Drivers properly.

adb shell

This command enables Android Debug Shell. Using ADB Shell we can perform several system actions.

su

This command requests superuser / Root permissions. Once the permissions are allowed, all the commands will run as the superuser.

setprop sys.usb.config diag,adb

This command enables Diag mode.

Method 3: Enable Qualcomm Diagnostic Mode using Terminal Apk

Step 1: Make sure your device is rooted and have proper root permissions.

Step 2: Install Terminal Emulator app from here.

Step 3: Connect your device to PC.

Step 4: Open Terminal Emulator App and enter the below commands:

su

setprop sys.usb.config diag,adb

These are the three methods using which we can enable Diag Mode and fix cannot find DIAG COM Port problem.

Have any queries? Ask them in the comment section below.