Eritosthenes

Not so fast. The clock display on my early 2007 vert vanished on April 5 after several hours of battery disconnection. It hasn't come back yet, even after more than a 1,000 mile drive home from NYC. All other NAV functions work perfectly. Looks like I'll be calling that special GM telephone number after all.

compyelc4

'07 Vert. 3LT, No GPS clock after disconnecting battery in February 2019 to replace seat covers.

cmonkey713

Very strange why some clocks came back and some did not on the same year model and NAV equipped. It will be interesting what GM has to say about this and if there is any fix in the works.

marinablu67

I bet you don't have ETA, if you don't have a clock?

wayback

2007 3LT coupe, still no clock.

Wierd how some 07 have come back on and some have not. Just my luck.

marinablu67

You're in good company!

Eritosthenes

I have "time remaining" in HH:MM, but not estimated time of arrival.

marinablu67

Page 2-41 of the NAV manual has 2 user settings, "Arrival Time G (Time of Arrival): This option will display the estimated time of arrival to the destination" or "Arrival Time \ (Time to Destination): This option will display the amount of drive time estimated to arrive at the destination."

Because I don't have a clock on my unit, I don't have either option!

compyelc4

True. Also GPS info screen says No GPS (GPS icon lined through) for quite a while, however GPS works perfectly during this NO GPS time. Ran GM diagnostics on GPS and it came back no problems. HA!

compyelc4

I've read hundreds of posts on this NO GPS Clock problem and your post is the first I've heard of this anomoly.

marinablu67

So what did that "special" GM telephone number tell you when you called? I can only imagine!

mkalush

Same problem on my 07. Can you give me the GM phone number to call? Thanks.

Eritosthenes

Call 1-800-222-1020. I believe the keys after that are 2 2 3 to get to Infotainment support. They will probably tell you:

1. They are aware of the problem.
2. The most recent tech bulletin on this subject is about two months old.
3. Hang up and go to a local dealer for support.
4. They cannot create a service request number for you.

#1 is true. They first started receiving customer complaints since late 2018. #2 indicates they've received enough complaints to prepare a formal tech bulletin. #3 means they haven't a clue what to do, so they want to divert you to somewhere else. #4 is complete nonsense. Lean on them firmly and they'll get you a service request number. You'll have to provide a VIN number and your e-mail address. After the call is over, they'll send you an e-mail like this:


They will advise you to take this information to your local Chevrolet dealership and have them establish a link with GM tech support with your service request number. This way your dealership can track the status with your VIN number. In theory GM should also be able to alert the dealership and provide corrective action if/when it is ever available.

A couple of observations...

-- The original problem is in the GPS firmware code provided by DENSO. The specific problem is the defined bit length of a variable named something like EPOCH_WEEK_NUMBER. In 2005 this variable was 10 bits long. (That 'epoch' is 1,024 weeks long in Base 10 -- about 20 years.) In 2011 or 2012 the U.S. Air Force upgraded its formal GPS communication software definition to change that variable to 13 bits long, growing the 'epoch' length to 157 years. The original DENSO code continues to to "parse" 10 bits of week number information out of each communications frame header, but after the change it fails. The variable is now three bits longer, and there's not enough room in the DENSO code to fit the 3 additional bits. That variable is used with others extracted from the frame header to compute the time. Please note that I do not have access to the DENSO source code, so this description may not be 100% accurate but should be quite close.

-- The only effective way to fix the problem will probably be for GM to contract with DENSO to build a new binary code image on a DVD like the annual updates that ended in 2016. There's no legal requirement for GM and DENSO to fix this problem, but it affects GM's two halo brands very visibly. There are some who might suggest that GM's bankruptcy releases them from any defective product liability, but many thousands of Corvettes and Cadillacs were sold with the exact same radios after GM emerged from bankruptcy. So they can't escape that way. The most effective way to get GM to fix the problem is for them towant to fix it, thus showing long term support and good will to present and future customers.

-- I believe our most effective channel could be thru CF member "Chevy Cust Svc". That member's job is to resolve customer problems that aren't being well handled by or communicated to Chevrolet. I will be sending a copy of this post and the first sticky under C6 Tech/Performance to Chevy Cust Svc.

Oh Boy

This a very real problem and effects a lot of Corvettes and Cadillacs. What the forum should do is get the ask Tadge section from the C7 hoarders and approach him with it. After all the ask Tadge section is really supposed to deal with the C5,C6,C7. This is a big problem and instead of the C7 section using it all for themselves and constantly asking Tadge stupid questions about the C7 maybe someone can ask there. If ask Tadge is really to be useful and do what it's supposed to I can't see of a better time than now.

compyelc4

Thank you for this information. Best I've seen. I'm sure we all appreciate your continued interest and help in getting this matter resolved.

compyelc4

Today I also found it this mess is affecting Ford Trucks as well.

owc6

Still not working, not expecting it to ever again.

marinablu67

I was kidding about the special number in my other post, but I have to say, that this is the most comprehensive explanation to date of what's going on! Thanks very much, and I hope that this situation is resolved very soon.

dr_gallup

Since the newer units like the one in my 2013 GS don't have this problem, it seems to me that the code must have already been modified and all that GM has to do is distribute the updated code to the owners of the older systems.

FortMorganAl

Have you ever tried to install Windows 10 on a computer bought 10 years ago? Sometimes a small difference in hardware makes future software incompatible. My iPhone is continually trying to update software to versions that are not compatible with my older model phone.