Hi all,

I have a 2008 ES 350 with 87,000 miles which has been trouble free until recently. The navigation system intermittently loses its GPS signal. By this I mean, the "GPS" mark on the screen goes away and eventually the navigation loses track of where the car is going. Sometimes the GPS signal will come back while I'm driving and stay working the whole day, other times it won't work for a day or two, other times it'll go on and off (the GPS mark) while I'm driving. I went into the diagnostic mode on the navigation and whenever the GPS signal is not working, the STS column of the screen which displays the satellites in use displays all "T"s - which according to the service manual means the satellite can be seen but isn't being used for location. When the GPS is working properly I see a mix of "T"s and "P"s - the P meaning the satellite is being used for navigation.

Anyone have this problem before and can it be resolved without replacing the expensive navigation ECU as the service manual has led me to believe? Thanks.