Cellular modem troubleshooting on Mesa 3 Windows

29 Apr 2022

If the Sierra Wireless EM-7455 cellular modem in a unit that is based on the Mesa 3 Windows platform will no longer connect, some methods to troubleshoot are listed below:

Verify SIM Card

Verify that the cellular data plan for the inserted SIM card is still active and fully paid.

Verify that the SIM card header pins are not damaged or missing.

Manually Connect the Mesa 3

  1. Go to Start > Settings > Network & Internet > Cellular.
  2. Uncheck "Let Windows keep me connected."

You can then manually connect your device. Once you are connected, we recommend re-enabling this setting.

Perform a Shut Down

  1. Go to Start > Power > Shut Down.
  2. Wait for the display and red LED light to turn off.
  3. Press the hardware Power button then let the unit complete boot up.

Uninstall and Re-install Drivers

  1. Go to Start > Settings > Apps > Apps & features > Sierra Wireless Juniper Mobile Broadband Driver Package (or similar name) and uninstall it. 
  2. Open Device Manager to look for any remaining Sierra Wireless related device drivers under Network Adapters, Sensors, and System Devices. 
  3. Open the View menu and select "Show hidden devices."
  4. Under Software devices, uninstall any "Cellular" connection (e.g., Cellular 18) and the "Mobile Broadband Firmware Device" if it is still present.

After uninstalling all related drivers and devices, manually re-install the latest drivers using the following file and instructions below:


  1. Download the file above to the Mesa 3 Windows unit.
  2. Extract all the files into the same folder.
  3. Tap and hold (to right-click) on the swsd007455iJuniper.inf file and select Install.

Note: No visual progress will show, and this can take a little time to complete.

  1. Once a message appears indicating it is complete, perform a Restart.

Possible Firmware Update

After waiting a few minutes, if your cellular service provider is not automatically detected, and/or the firmware does not finish loading (you could see an Error 77), then remove the inserted SIM card and download and run the following firmware install files. Note: These files are carrier specific for Verizon and AT&T.
If you are planning to switch between networks, download and install all that apply, but run the one for your preferred network last.

Firmware for Verizon customers: SWI9X30C_02.30.01.01_00_VERIZON_002.052_004.exe

Firmware for AT&T customers: SWI9X30C_02.30.01.01_00_ATT_002.049_005.exe

Firmware for all other carriers: SWI9X30C_02.30.01.01_00_GENERIC_002.045_002.exe

Manually Apply APN Settings

If Windows does not automatically detect and load the correct APN settings for your cellular network (based on the inserted SIM card), you can use the Sierra Wireless Skylight app to correct the APN settings. Follow the directions in Apply an APN with Skylight.

Related Information

Additional suggestions are provided in Cellular settings in Windows.

If needed, the unit can be submitted to a certified repair center.