micwhitt1

I purchased my 70th AE on 5JUL2023. On 4AUG2023, I went on an almost two-week business trip. When drove the car again on the 18th, I noticed the posted speed limit was not displaying in the HUD or dash cluster. After a little research, I found the following in a GMC Arcadia forum:

"Well, here's the scoop on the "heads up display" local speed limit on GM vehicles. After many calls to GM headquarters and to Onstar, I have a solution for you. First of all, the HUD probably will be free for the first month after purchase. Then, only part of the HUD will work. The local speed limit is omitted until you purchase Onstar with data. "

Can anyone verify the accuracy of the above information and its applicability to the C8?

gliot1

My Onstar has expired but the speed limit is still showing on my '23.

proeagles

I never had OnStar and my speed limit is posting when it's available. Might be a 23+ thing trying to get people to waste their money on OnStar.

Red rag

My 23 displays fine without onstar. If it’s a road without a sign posted sometimes won’t pick up. Does it happen 100% of the time?

tadda

Same here on my '23

The speed limit display is tied to the C8s Nav system and posted road signs and has nothing to do with OnStar....

micwhitt1

Happens 100% of the time. Driving I-275 and throughout the Tampa Bay area with posted speed limit signs, but no speed limit showing in HUD or dash cluster.

tadda

Do you have your HUD display specially set to tour mode? Posted limits will not show up on HUD display if set to Sport or Track default HUD settings...

To clarify further...I have my HUD setup to display Tour mode on the HUD even when I select either Sport, My Mode, or Z mode for example...

While in the Drive Mode of your choice (My Mode, Z Mode, Track, Sport, Tour, etc.) go to "Design Display" and select "HUD"



In HUD you can select either Tour, Sport, or Track...If "Tour" is selected then posted speed limit will appear in HUD...

If you want posted speed limit to appear in the HUD for all the Drive Modes for example, you'll need to set HUD display to "Tour" for each of the drive modes...

micwhitt1

I'll check that later today. Thanks!

Zymurgy

The speed limits are in the Map database and have absolutely nothing to do with OnStar.

Jbyrd43

Try to use your nav to see if it loads. If it doesn’t, take it to the dealer. There’s a known bug (according to my dealer) and they basically have to flash the nav or give you a new memory card.
It happened to me when I first bought my 2023

c6miller

I had a similar issue with my 2021 HTC. You may have a problem with the SD card for the NAV. Try to remove it and reinstall. You may need a new one under your warranty

Red Mist Rulz

That's completely wrong, at least for a C8.up through 2023 MY

The HUD is free. period. The only thing related to OnStar is turn by turn directions IF YOU ASK ONSTAR TO DOWNLOAD THEM TO YOUR CAR.

The PSL is stored on the map database SD card, as part of the data for a given street & location. The data doesn't exist for every piece of road, and sometimes it display as blank. But it should display on most roads, and always on interstate highways. If you usually get the PSL displayed, but it's occasionally blank, probably nothing wrong. But if it's never showing, or sometimes shows on a given road and sometimes doesn't, that's an issue.

Note I said through the '23 MY. For '24, the C8 gets a whole new system built around Android Automotive and Google Maps, and will lose functionality without a subscription.

Red Mist Rulz

Actually, it's tied ONLY to the map database. Some cars have cameras that read speed limit signs, but the C8 does not.

Andybump

This is not true for 2023 and prior model year Corvettes (I don't know about Acadia). However it will be true for 2024 Corvettes due to the new approach for the Navigation system (which can be reviewed in the 2024 Owners Manual). The new approach replaces the current on board navigation software with "Google Maps". There will not longer be an on-board SD card for the maps. Instead Google will download the maps as needed in real time to support navigation. And that is where the speed limits will come from. A data plan is needed to support that according to the 2024 Owners Manual and also the the information that can be found at the link given in the 2024 Owners Manual. It may (emphasis on may) be possible to work around that if you set your cell phone to act as a hotspot. Your can can then connect to the phone as if it were any internet enable network (I have verified this). And it can then be a source of data for supporting some (emphasis on some) of the on board apps. Forum members have reported using their phone like this for current models. However, it may or may not be possible to support the built in Google navigation software that way on the 2024.

JerryU

If it is intermittent, as mine was for a year, could be another issue!

When I had free XM Radio for a year all was fine. At the end of a year I started to use the Thumb flash drive I used in my C7 with >1000 songs. It was fine for about 2/3 of my starts and then got a message on my dash display that said SD Card removed (note that short message did not say NAV or PDR SC Card.) . Press Nav to display on the center screen and the message below appeared.

Turns out it is a problem with GM cars/trucks using the same Infotainment system. A member found he was able to solve it by reducing the song bit rate on his Flash Drive. He concluded after a number of tests, that NAV and the Flash drive were loading on the same buss and there was a conflict and the NAV was not initiating!

I did what he suggested and the problem reduced to ~15% of the starts. When NAV is not initiated NO SPEED IN HUD etc! PIA as use speed limit far more than NAV, No solution from GM for C8 or other cars and trucks, One bulletin for other than the C8 said it a software anomaly! Zero help! Posted issue on forums for ~1 year, got suggestions - none worked.

I was at the dealer for another reason and their great C8 Tech tried reloading the Infotainment software- NO help. Then the TECH read another techs note on the GM Service Computer. It said IF using a (market leading Brand) flash drive this can cause the issue. I did not mention the brand BECAUSE SOME GET THEIR SHORTS IN A KNOT. I HAVE USED THAT BRAND FOR YEARS WITH NO ISSUES. BUT switched to a new Verbatim thumb drive and have not had that reoccur in >1 year. The Tech said there was no explanation of why that Brand was mentioned and they often put notes in on something found, even if it's not known why!

I explain in detail what I think it MIGHT be in my PDF. It could be a bootlegged Thumb drive as I bought from Amazon. It could also be as I used that thumb drive in my C7 for >3 years (but as my PDF notes also bought a new one) that the C8 new infotainment system requires a faster reading device. The fellow that found the bit rate solution tested and:

• If he started without the USB flash drive for music all was fine.
• When he used his original high bit rate the issue returned.

You can google and see it is NOT unique to the Corvette. I even paid for a new NAV card with no help.

The Solution is shown in this PDF (if you don't want to download AND have the issue shown in the pic, PM :
http://netwelding.com/NAV_SD_Card_Error.pdf

Ystayhm

i have a 2020 I found that the issue with mine was I needed a map update which I purchased for $100.

micwhitt1

Note to self: Always make sure the NAV SD card is fully inserted.

fastoy

My experience is that if my iPhone is using another Wi-Fi network, e.g., acting as a hotspot, CarPlay won't work. I don't know about Android Auto but I'd expect it to be the same.

Andybump

See this thread and let me know if made a mistake. I was able to connect the phone, acting as an external network, and still supported carplay.

https://www.corvetteforum.com/forums...taneously.html

JerryU

It's spring loaded hard to miss!
FWIW for the Intermediate issue I posted (with pic) in # 20 above. It unfortunately occurs intermittently in other GM Vehicles with the same Infotainment system:

I and others tried many things (in my case for ~year.)
A Dealer replaced a members the NAV SD Card Reeder (no help)
I Bought and undated NAV SD Card (no help)
I Cleaned the contacts a number of times and increased card reader contact tension (with thin plastic over card -no help)
Turns out has nothing to do with the card reader!

This is what the conclusion was in a GM Service Bulletin # 19-NA-279, I believe for a Silverado as others had the same center screen message as I did:

• Some customers may comment on Infotainment software issues.
• SD Card Error code 0x40000 • SD Card Removed message when card has not been removed •
• Cause: The cause of the condition may be software anomalies.