Hey everyone, I'm looking for some assistance or troubleshooting ideas for some problems with my C7. About 18 months ago my 2015 Z51 started experiencing multiple issues that I think are all related somehow. Below is the list of issues I've noted:

1. Time on infotainment screen will not auto update
2. Nav cardinal direction will not display on dash or infotainment screen
3. MyChevrolet App will no longer lock or unlock doors or trigger alarm
4. I no longer receive monthly "vehicle diagnostics" report emails from OnStar

Lastly, pressing the OnStar button on my mirror will not call OnStar and sometimes I get a red exclamation mark in the mirror, indicating an error.

I know what the owners/infotainment manual says about driving in a circle to calibrate the Nav and understand that the symbol in the mirror means there is something probably wrong with the OnStar hardware, but could it be that a shared antenna or antennas could be the root cause of everything? Let me know you thoughts and suggestions!

 

I don't have an answer for you on the clock or compass, but I do know that the fob and diagnostic report features of the app only work for five years from delivery date unless you subscribe to Onstar. Mine is a '14 and the app stopped at five years. I am pretty sure my Onstar buttons on the mirror would still work though if I wanted to call them to reactivate. They are still lit up normally.

Good luck with it!

 

OnStar uses an antenna mounted in the windshield header for GPS and cell signal. This antenna is shared with the factory nav system, if you have it. I'm not sure if OnStar's compass is internal to the module or if it somehow uses the antenna.

I do know that removing the cellular sub-module from the OnStar unit causes everything you described. So it's possible the cell board went bad. GM doesn't service that separately though. Used OnStar modules are cheap though. They're not Corvette-specific. You just need to find someone to program and activate it for you.

 

Did your car still have the basic OnStar service and it expired??? Just another thought. All the best.

 

Compass without factory nav is based on the gps. Do you have a red X instead of direction? Does indicated direction change? Onstar / diagnostics would connect by cell.

Sounds like common cell / gps antenna issue.

Did you have any work done recently like a windshield replacement? I lost gps / compass after a windshield replacement.

GL

Ron

 

Thanks for the responses. Ron, I do not have a red X, just two dashes on the dashboard display (see pic below) and indicated direction does not change. It's the factory windshield and I also tried to call onstar today via the mirror. It will not complete the call and gave me the error exclamation on the mirror (see pic). I have narrowed it down to the cell/gps antenna or the VCIM (Onstar module behind the glovebox). I figured the antenna probably has less of a chance of going bad than the VCIM (many have reported issues with the circuitry). Since my bluetooth is still working and the GPS displays dashes instead of a red X, I am going to attempt to replace the radio board of the VCIM without having to replace the whole module and have it reprogrammed. I'll report back if that doesn't work, as the next possibility is the gps/cell antenna itself.

 

OK. After I had my windshield replaced, my direction indicated N and would not change. The windshield guys came out and disconnected / reconnected all the cables around the mirror and I got a direction after driving less than 100 ft.

There were several thread about a red X indicating a cable issue.

Your indications and issue appear to be different.

Direction appears to be calculated from 2 or more gps position fixes. Maybe the dashes mean no calculated direction from the VCIM module as you suggest.

GL and keep us posted.

Ron

 

An update for all interested and anyone in the future who experiences these issues: it was the radio board of the VCIM! Luckily the modules are a dime a dozen at junkyards and dont require reprogramming. I now have all functionality back (direction, calling, etc). Hope this helps someone!

 

My 2015 came to me last week. It has PDR, Z51, mag ride, 2LT and a stick - fun! However it also came with the Red X, no gps signal, no auto set clock, and the Onstar won’t make a call. I also discovered that when I make a Bluetooth phone call, it goes through and I can hear the person - but they cannot hear me. Otherwise, much as described above. I went through the service bulletin steps (dealer did the PDR module update with a SD card for me the night I picked it up) and I later did the foil tape wrap of the antenna leads up over the mirror. I saw no pinching or other damage to any cables while in there. I unplugged and re-plugged the HMI connections to no avail. When I enter the diagnostic mode it still sees no satellites. From reading these threads I plan to next check the connections on my VCIM, and then the antenna splitter which appears to be nearby, accessed from under the glove box. Do those go bad? From there it appears that I would suspect a failed board in my VCIM. Have others found something else to check? The issue seems to be both gps and Onstar so I’m looking for where they co-exist. In a couple days I will have a simple dash-mount fakra blue (C) gps antenna (thanks Amazon Prime) to plug directly to my HMI in place of the factory right angle connector there now to see if that gives me a nav signal.

As for the VCIM, from above I understand that if I replace the Onstar module (VCIM) with one sourced online, that is a direct swap out, no dealer programming needed. Are we really getting that good a break on solving a car problem these days? It appears that 84024907 is the current part number, and the label should read 84022585 for the version with Wi-Fi hotspot - our cars have this? If no hotspot, the label then should read 22833630. Do these numbers track with other folks who’ve had to go through this?

I want to upgrade the HMI and ACM to get faster nav, car play and HD radio but these things should be sorted first.

thanks to all for posting up about these things and I will add my results once I get it all to work.