I can't seem to get rid of error 131 (serial timeout) on a 4163 controller.

Its connected over ethernet and the serial port isn't even used.

I tried downloading a program from the controller into the editor to see if anything might be auto-running on boot, but it seems clear. No program scanning or polling.

I tried "CW,1" even though its apparently not a supported command on the 41x3 controllers and it did nothing.

I tried setting a handle for unsolicited messages, but I believe GalilTools does this automatically anyway when it's launched.

If I issue a series of TC commands fast enough it does eventually clear, but after a couple seconds it just comes back again.

I'm really out of ideas on what's trying to talk to the serial port and jamming up the error code. Any suggestions would be appreciated.