Speed limit in Nav and DIC

[Cupton]

Dumb question and I was going to ask the dealership at my last oil change but I forgot so I thought I'd check here. How is the speed limited updated in the Nav and DIC? When I first moved to Pennsylvania in 2015, shortly after they made the turnpike speed limit 70mph. I bought my 2105 Sierra about that same time and wasn't surprised to see that the truck was still showing the speed limit as 65mph when it had recently been changed to 70mph. Fast forward 3 years, I trade my 2015 in for a 2018 and it STILL shows the speed limit on the turnpike as 65mph. Not just on the turnpike, but quite a few places I've driven its been off.

 

So what gives? Thoughts?

[2018GMC]

I believe it gets the speed limit info from Sirrus xm. 

 

Ive noticed mine doesn’t work on most rural roads or city streets. Only works in main highways and Interstates. 

[Jaychevy81]

Mine is the same way usually off on the posted speed limit drives me nuts to lol.


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[Jaychevy81]

So not sure if this helps just did a little searching. A online GM site said it uses the camera behind the rear view mirror to read the posted signs. Not sure how true that is but maybe why it does not register on local streets idk?


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[Nitrousbird]

23 minutes ago, Jaychevy81 said:

So not sure if this helps just did a little searching. A online GM site said it uses the camera behind the rear view mirror to read the posted signs. Not sure how true that is but maybe why it does not register on local streets idk?
 

If that were the case, then it would always read blank until a speed limit sign was passed.

 

As for being accurate - just run Waze via Android Auto/CarPlay and it will be up to date without any concern for updating.

[GTPprix]

Its part of the Map database; Update the maps update the Speed limit data ;) 

[Cupton]

38 minutes ago, Nitrousbird said:

If that were the case, then it would always read blank until a speed limit sign was passed.

 

As for being accurate - just run Waze via Android Auto/CarPlay and it will be up to date without any concern for updating.

I normally do run Apple maps through CarPlay but I like having my current speed/speed limit screen up on the DIC too. I thought that a new truck would of been updated 3 years after the speed limit change on the turnpike. Sheesh.

[Bob985]

It gets the speed from the factory nav