Lost time display on C6 Radio/NAV screen
 

Feel like rolling up your sleeves on a rapidly growing C6 problem? Apparently all of the radio/NAV head units for 2005-2011 need new firmware to calculate the time of day. When the Air Force updated its Global Positioning System in 2011 or 2012, they redefined and enlarged a bit field for the week number field from 10-bits to 13-bits. In doing so, they created a Y2K-like problem when the week number rolls over from 1023 to 0 (in base 10, of course). In late 2018 this field rolled over for the second time since 1980, and C6 time displays started failing. The time display continues to work fine until the battery is disconnected. When the battery is reconnected, the system reboots but can't find a 10-bit week number it's expecting in an updated 13-bit GPS broadcast field. The clock display is a blank box. (GM appears to have been aware of this change since they changed the head unit part number for the 2012 model year.)

Last Saturday evening the clock display failed in my 2007 3LT convertible when we reconnected the battery after some engine maintenance. I have a Service Request Number which I can provide privately. The VIN is 1G1YY36U375104442. My local dealership, Schmitt Chevrolet in O'Fallon IL, is aware of the problem. They're unable to fix it, of course.

As a retired engineer myself, it seems to me the only way to fix this problem in GM's Corvette and Cadillac halo brands would be to re-open the support contract with DENSO. They own the proprietary source code for the head units. They could update it and distribute it the same way the annual NAV DVDs were until 2016.

For more information, please refer to the sticky post in the C6 Tech/Performance forum, and to this post in the C6 General Discussion forum.

Please help us. I've already sent a PM to Corvette Forum user "Chevy Cust Svc" to try working this up the customer relations ladder. But if you can weigh in on the engineering side, I think our chances of success would be a lot better.

V/R
Robert G. (Doc) Savage
112 Lakeland Hills Drive
Fairview Heights, IL 62208-3432
E-mail: dsavage@peaknet.net
H: 618-235-6548
C: 618-530-3848

This seems to be a significant issue for many older corvettes with factory nav units. Although I don't believe there are any federal or state requirements.I would think that GM building cars with equipment that has a less than 10 year design life and then ignoring the problem would create a marketing issue in the future.

The GPS system change that triggered the April 6 week number rollover is affecting a lot more than C6 radio/NAV time displays. It appears that any GPS system or subsystem that failed to implement the pubished changes to the GPS broadcast standard is now broken. New York City and Northrop-Grumman failed to update their NYCWin system, and it also failed on April 6. They both seem afraid to admit there's even a problem, while struggling to find a solution.

GM engineering is aware of the issue and there is supposed to be an update in the works. They had a service bulletin (# PIT5652A) that was released on Feb 8,2019. It's effecting more than just Corvettes, but they have a temporary fix available for the SUV and trucks, but nothing yet for the Cadillac and Corvette vehicles.

In the interest of customer satisfaction, we now warn customers that come in for programming and/or battery replacements of the issue and let them decide if they can live without the clock until there is an actual fix.

Yes a quick answer from Tadge would be welcome.
Perhaps make this month's question to him two parts, such as:
Part 1 "Tadge, you may know of the C6 Nav clock issue, will GM fix this soon?"
Part 2 "Will the C8 be have cup holders?"

2006 Corvette with navigation
 

When you change batteries or otherwise disconnect customers can't you hook up a battery charger to the jump start terminal and a good ground (as shown in the Owner's Manual) before hand so the clock won't lose power?

Hmmm... why is there no reply from Tadge? According to GM records this issue effects all 174,000 Corvettes sold between 2005-2010. Not an insignificant problem.

Because that's not how "Ask Tadge" works. He doesn't read this forum, he reads the question I send to him at the beginning of each month.

That number seems high. I believe it would be more in the 75,000 range. Still, 75,000 Corvettes (ignoring the tens of thousands of other GM vehicles with the same issue) that are no longer working as designed because of a factory error would seem to be a significant black eye for GM. Granted GM didn't expect Denso to make such a major error but people who buy Corvettes think they are buying Chevrolets, not Densos. And it is GM that is going to get the blame.

any time you have to disconnect the battery use one of those 9 volt battery adapter into the lighter port.

Obviously not a good idea if you are working around armed air bags.

if you are worried pull the air bag fiuse

Unfortunately this isn't the kind of problem you anticipate when you simply change a battery.....Hopefully a solution soon but I'm not holding my breath.

,I have been doing this since they put computers in cars so you did not loose the radio station settings

Good advice. What’s weird is that I did not lose any of the radio presets even know the battery was disconnected.

Does anyone think Chevrolet cares about problems with 10 - 15 year old cars? They don't care that much about late model cars. Look at the history with LS7 valve guides. And more recently, all the problems with C7 automatics. As long as the warranty cost is manageable they don't do anything to fix the real problem. Out of warranty? Fuggedaboutit!

I guess we were thinking that since this effected tens of thousands of C6's (174,000 were sold 2005-2010) that it would be an obvious question to ask him about. Not to mention it is such an unusual problem.

We really are wondering what caused the problem and what the prospects are for Chevy to resolve it. Any news would be appreciated.

Hey folks -

For reasons that will become obvious shortly, we're not going to be able to send this to Tadge. Like RichieRich suggested in an earlier reply, the folks at GM know about this and it's affecting a bunch of vehicles; not just the Corvette (and not just GM vehicles...). GM doesn't have a fix for the Vette yet, but they're working on something. There's no ETA on it at the moment.

This is all Tadge will say in his response. Given that, I see no reason to send it to him.