I went from sync 2 to sync 3 A few months ago and I have installed external GPS antenna for the sync 3 unit.
Everything Was Working Fine Until Two Days Ago. The GPS on the unit started showing that I was 10 miles away from more I actually was. I took the head unit out I pulled the GPS I put it on top of the – drove around for a little while that did not change anything. The weird thing is, I was playing with four scan right before I noticed the GPS thing I’m not sure if they are even related or if it just a coincidence. Is there any settings in for a scan that I could have changed that could mess with the GPS location?

 

I would post this question in the FORScan sticky.

I would think a hard reset... pulling the positive battery cable off for 15 minutes and then reattach. Admittedly that is nothing more than a guess.

 

I tried a master reset on the unit, didn't do anything. I'll try the battery next and I have a new gps antenna on order. Just in case.

 

I did a hard reset on my 2016 with syn3 the compass was not working
After a few miles it reset
I have to reset to show North at top

 

Is hard reset same as the master reset ?

 

What were you messing with (forscan)?

 

Mainly w BCM. SETTING DRL and flashed FCIM WITH MY as built data to see if I can get rid of some of those DTCs.

 

Since GPS is calculated out - in the software there are various adjustments as well as test loops.

One of the things in Vehicle GPS is to have an offset adjustment such as to understand the antenna is here - but the center of the vehicle is ______ thus offset the calculated position by ____________. In each direction. (often only X and Y where Z would be vertical)

Anyhow it might have gotten confused and you need to do a full set of the GPS Computer - like how sometimes your smartphone forgets exactly where it is. Full power cycle reset forces the GPS to recalculate from scratch and it might re-center it self.

I would try that first.

after that I would try re-loading/flashing the GPS software

 

Can u walk me through that process. So what exactly needs to be done ?

 

Is the tire size programmed properly into the APIM and the same for the GPS antenna location? Did you by chance change tire size in the BCM?