2016 Yukon - Replaced GPS Antenna AND HMI - NAV Still not working

[e3gordon]

1st post on the Forum - Long time Yukon owner/fan

In the process of purchasing a 2016 Yukon SLT with 91k miles from the dealer.
Clean history, and excellent maintenance records. I want the truck For wife and kids.
Had a couple of things fixed on it and have one lingering issue to go before we move forward.


Truck reading "CAL: in red on driver info cluster. GPS non-functional.

1. Truck had one previous replacement of the high frequency antenna at 35k miles a few years back for reference. History shows the previous owner took in before selling to calibrate the compass at another dealer. Likely didn't fix the issue.

2. Dealer orders and installs new shark fin antenna - runs checks/calibration, says antenna is sending info (old one wasn't) but car still reads CAL, GPS not working.

3. Dealer orders and installs new HMI module, allows car to "sit out" and drive to calibrate as they said. Compass briefly works then reverts back to "CAL" and red x through NAV icon on screen, maps showing but the location is severely off and lagging. The bottom line not working.

4. Service manager opened case with GM Tech Assistance - suggest replacing junction splitter line?

It's going on two week process and want to know if any input or other items could be causing this..
They checked the battery thoroughly too which I know can create some tech glitches if bad.
Not to say I doubt the techs in service but have a lot of faith in this forum to id some additional items to check into.
Wife has been patient but really want to get her this truck!

MUCH APPRECIATED

 

[e3gordon]

1st post on the Forum - Long time Yukon owner/fan

In the process of purchasing a 2016 Yukon SLT with 91k miles from the dealer.
Clean history, and excellent maintenance records. I want the truck For wife and kids.
Had a couple of things fixed on it and have one lingering issue to go before we move forward.


Truck reading "CAL: in red on driver info cluster. GPS non-functional.

1. Truck had one previous replacement of the high frequency antenna at 35k miles a few years back for reference. History shows the previous owner took in before selling to calibrate the compass at another dealer. Likely didn't fix the issue.

2. Dealer orders and installs new shark fin antenna - runs checks/calibration, says antenna is sending info (old one wasn't) but car still reads CAL, GPS not working.

3. Dealer orders and installs new HMI module, allows car to "sit out" and drive to calibrate as they said. Compass briefly works then reverts back to "CAL" and red x through NAV icon on screen, maps showing but the location is severely off and lagging. The bottom line not working.

4. Service manager opened case with GM Tech Assistance - suggest replacing junction splitter line?

It's going on two week process and want to know if any input or other items could be causing this..
They checked the battery thoroughly too which I know can create some tech glitches if bad.
Not to say I doubt the techs in service but have a lot of faith in this forum to id some additional items to check into.
Wife has been patient but really want to get her this truck!

MUCH APPRECIATED

Head scratcher

 

[tom3]

I've read the HMI module must be programmed for the vehicle VIN to work? Surely the dealer would know this if so. I'd keep looking for a different vehicle if they can figure it out and give decent warranty on the work.

 

[e3gordon]

I've read the HMI module must be programmed for the vehicle VIN to work? Surely the dealer would know this if so. I'd keep looking for a different vehicle if they can figure it out and give decent warranty on the work.

Appreciate it Tom, I’m going to relay this point to the service mgr tomorrow to inquire if this has been done. Yeah for sure you would think that would be part of the replacement installation steps though…! Thanks

 

[e3gordon]

UPDATE: New Junction Splitter connection installed. GPS and Nav worked briefly but dropped off and again compass reading "CAL" on info cluster and Nav inoperable. Not sure what the hell else could be causing it not to work...

 

[e3gordon]

Couple days later, more troubleshooting - gps and compass works for a couple hours after car sits outside overnight then drops off again.

 

[Doubeleive]

you might try a 3rd party gps antenna and just plug it into the hmi and stick it up under the top front part of the dash. I f that works then route it under the front part of the dash plastic as far forward as you get it.
they are like $25-30 on ebay. I have one in my 18 silverado works fine. it didn't work great at first and then I reprogrammed the radio (via: acdelco tds, same thing the dealer uses) and it started working much better.

 

[e3gordon]

Thanks I’m relaying the input to the dealer. This is helpful. They are re-assigning it to a new tech.

Did you have the same issue?

you might try a 3rd party gps antenna and just plug it into the hmi and stick it up under the top front part of the dash. I f that works then route it under the front part of the dash plastic as far forward as you get it.
they are like $25-30 on ebay. I have one in my 18 silverado works fine. it didn't work great at first and then I reprogrammed the radio (via: acdelco tds, same thing the dealer uses) and it started working much better.

 

[e3gordon]

UPDATE:

Dealer installed new on star module and it all works!

Combo of antenna and onstar module talking to the driver instrument cluster and hmi to nav screen and voila.

Hope this helps others. GMC techs and technical service advisors did not reccomend - Fix came from this forum.

2015i Tahoe GPS issue

The issue I'm having is on the nav screen in the upper right, it says GPS with a red x through it. I brought to dealership and they had a software update that seemed to fix it for about a week now its back. anyone else having that?

www.tahoeyukonforum.com

Thank you!!!