My tomtom is waiting for valid gps signal
As you probably know, the GPS device needs to get a satellite signal to determine its (your) location, before it can be used.
When the device is having difficulties getting that information, that message is displayed.
A common reason for not being able to get the signal is when there's physical barriers between the device and the satellites, e.g. when you're in a building, under certain covers where there's little/no line of sight between the device and the satellites.
Sometimes, even when this is not the case, the GPS has difficulties getting satellite signals.
So, getting an update (from the tomtom webiste) of the satellite locations can help. Just connect your GPS to the tomtom website, using tomtom HOME (the software), and get the QuickGPSfix update (a very small file) installed on your GPS device. It is suggested you update this data regularly ( as it provides a better location of the satellites, for the GPS device to search)
If you've already done that and the GPS still have problems locating the satellites, try to reboot the GPS. This can be done by holding down the ON/OFF button (for quite a while, e.g. 30 seconds or more) ... to shut the GPS down, and then turn it on again. Or, use a pin (e.g. paper clip) to press the "RESET" pin-hole, to turn it off, and start the GPS device up again.
Hope this helps.
on Jul 12, 2019