GPS very slow or stuck - EM7455

I have a handful of Panasonic CF-33’s, all of which have the EM7455 card with LTE service via Verizon. Currently, four of these units are in service. One of which has been flawless since day 1 several months ago. The other three, put in service last week, are very slow with GPS coordinates or even stuck. Positioning is at least 60-90 seconds behind realtime location and can get up to several minutes delayed, if at all. I am at my end figuring this out as I have never seen this behavior before. I have well over 100 Dell laptops with their DW Gobi product manufactured by Sierra Wireless, all using the GPS without problems. But these three units are making me pull my hair out.

All three of them are running Windows 10 1803. Drivers and firmware are up to date. Using the Sierra Skylight connection manager.

Would anyone be able to point me in a workable direction?

Can you open a hyper terminal and issue the following AT commands and get us the output please?

Apologies, but I’m not sure I know much about doing hyper terminal. What utility is the best for that?

You can download PuTTy from their website below.

First you need to identify the modem port number by checking Device Manager under modem. Then open Putty and select Serial and modify the Serial Line to match the modem COM port.

OK…go that far. it’s just running lines of code. where do i issue the commands?

Once you got all the setting right, click on the Open button at the bottom of the screen will get your a terminal window where you can issue the AT command.

Wait a sec, did you download the msi version and installed the Putty application? You can download a .exe executable instead which you can click and run directly without installing it.

important gps commands:
AT!CUSTOM=GPSSEL,1 to set antenna to diversity antenna
AT!GPSPOSMODE=F7F , defaults to 1 which is standalone GPS, very slow
AT!GPSAUTOSTART=?, then set to 2 so it automatically starts the GPS when the NMEA port opens up.