Sync 3 update grade nav is off by a little

[Dukesjunk]

I have upgraded to a sync 3 and have programmed with forscan to get climate control to work and everything else works except Nav

I have the Nav button, I can see the map but it's showing me anywhere from my actual location to start then as I drive it shows correct direction of travel but shows me going significantly faster than I'm actually traveling which means the longer I drive the further from my actual location it shows me.

I've tried changing the code for location of nav antenna to reflect its true location on the dash. I've tried 2 different antennas both purchased from amazon with blue fakra connection.

On a couple of occasions it's even corrected to current location when I've been sitting still for a few minutes or once when I did a 3 point turn on a side road.

Any suggestions?

Thanks
Duke

[buckeyesvt]

Did you copy all the settings over? There are some specific settings in the APIM that are for revolutions per mile for calculating the speed of the nav vs actual movement. I would select the same truck with same options (i.e. 2016+ with same engine/ and rear axle ratio) and copy APIM config out of the As-built and compare. I believe you will find your issue there.

[Dukesjunk]

I figured there were some settings for some sort of dead reckoning.

Anybody know what line and spot those settings are in for the f250

[Dukesjunk]

Will changing tire size in the 726-12 block effect a change in the navigation or is there also a location to change it in the APIM module?

[Dukesjunk]

I will answer my own question a bit,

It’s not the 726-12, I think its the 726-44 that changes tire size

I had previously had about a 20% discrepancy in the circumference of the tires I was running and what was in the original as built coding.

This wasn’t enough to warrant calibration when the speedometer was all that was off, but with navigation apparently they system relies on occasional satellite updates and uses the dead reckoning of the trucks travel and direction to keep you on the maps.

I found that before I updated the tire size in the computer, I could travel to a location and the latitude and longitude would be correct for the location but the map would show I was somewhere else.

Once I updated the tire size code to one that was very close to what is present on the truck I’m getting much more accurate location on the map.

Duke