leres

What part number is your radio? The first post in this thread shows how to get to the diag screen: Pretty Sure You Can Now Pull OBD2 Diagnostic Codes From OEM Nav Screen (pics)

The battery voltage doesn't go to zero when ACC runs the battery down so it could have been that his radio never completely lost power.

robertfa

I agree! See post #656 and 674.

scummins06

Went for a short drive today. Glanced at the clock an it's working again. the time was off by two hours but I was able to reset to the correct time. It does appear that the GPS time is off one or two hours depending on daylight saving time

robertfa

How about the date??? 2001???

Rocketman7

Absolute complete and total BS. Completely unacceptable that GM would not have anticipated this problem or would not have it fixed since this first surfaced. Absolute garbage. If this happened in my department people would be gone. In fact I would have been gone by now would have been my expectation.

scummins06

Sunday December 31st 2000. Well at least I have a clock & Navigation works.2 out of 3 is better than nothing. Most of the time I know what the date is without looking!!

tommyc6z06

This was just the required impetus to upgrade to a contemporary head unit with Bluetooth, CarPlay and front/back cameras.
And this, from someone who rarely even listens to music in this car as I prefer the engine sounds. But no clock is a deal breaker.
And BTW, all manufacturers suck when a car is out of warranty and a gen or two older

Albie51

Me too. Recently woke my '07 from its winter nap and found the same "clock not working" problem. I disconnect the battery and connect a battery minder to for the winter. I'll stay tuned to see if a fix is discovered.

bikingles

Lo and behold got into my 06 vert yesterday and clock came on after three months of a blank screen. Time was a few hours off but I was able to reset it. Year showed 2001 but line thru the GPS was gone. Hopefully everyone here who has the same problem will have it resolved soon. GM was no help they had know idea what I was asking them about.

mkalush

Great to hear....Hope I'm as lucky with my 07!

robertfa

Curious that nearly everyone (see below) who got their clock back, got a date of late December, 2000 or first day or so of January, 2001.

Post#599, Post#743, Post#763 and now Post #769

Also, seems to be a small percentage of us that are getting back the clock. Wish I knew why some are coming back and many have not.

compyelc4

Then if his battery never lost all power after his clock went out then how did a jump bring his GPS clock back? Sounds sketchy to me.

leres

I think the blame lies the lazy software engineer(s) at Denso who wrote the original radio firmware. This is a tough one for GM; they didn't design or manufacture or the navigation radio and have no in-house ability to correct the problem. So they have to go to Denso for a fix. And if Denso did produce a fix, somebody would have to pay for creating DVDs, distributing, them, etc. And if thousands of radios get this fix, you can assume some number will fail. This is liability that nobody wants. Not GM, Chevrolet, Denso, your local dealer, etc. I'm fully expecting nothing to be done by GM. But it seems that one of bollman's guesses was correct:

Which seems to be the case given the reports of radios working but with the year reported as 2001. Really, that isn't really be so bad.

Meanwhile GPS uses two data sources to work, almanac and ephemeris data. The almanac has satellite orbit information and is like the roadmap of when each satellite will be where. It's transmitted every 12.5 minutes and is valid for up to 180 days.

The ephemeris data is much more detailed but is only valid for 30 minutes. But it's broadcast every 30 seconds so it is easily acquired by the GPS receiver.

When you turn your car on your GPS usually has a valid almanac and with a good view of the sky can get copy of the current ephemeris data and then calculate a fix within a few minutes.

When you remove the battery or pull the radio fuse the almanac is lost. Next time the GPS fires up it has to collect a complete almanac. So it takes a minimum of 12.5 minutes before it has all the data it needs to navigation. But since nothing is known, the GPS can't predict which satellites should be visible and when they will travel under the horizon (and no longer be visible). So in practice it can take a lot longer. It's much better when you start out with a valid almanac.

Given the way our radios work if you hook your battery back up there is zero chance your clock will work until you no longer have a line through the GPS icon. And although the year might be displayed incorrectly, if the GPS can get a fix, it knows the correct time. It has to because time is fundamental to the GPS protocol. You know what time it is, the satellites broadcast their time; you subtract the two and calculate the distance to each satellite. Then do some "math" and figure out where you are.

It's the software that translates the GPS version of time to a human readable format that's broken. Some faulty code mangles the translation, some other code realizes the date makes no sense and refuses to display it. (But not allowing non-GPS, manual setting of the clock -- that's unforgivable..._

As I said, this was another possibility. Later he reported his clock had the wrong year so obviously this wasn't the reason.

Example of what I was talking about:

12V Automotive Settings Keeper w/9V Battery - Keep your Personal Settings when Replacing your Car Battery

ATLZ06

"Most" of the cars that have clocks that start, "working", are 05-07. I say most because we only know what's posted here and I thought I remembered an 08. I have an 08 and my clock is still waiting.
I tried everything most people did, battery disconnects and resetting anything I could on the radio. All the diag screens don't help but I compare them to the other posts. It seems like they referenced a date in their code as people speculate and depending on how it was done we may see the later years follow. Just speculation like everyone else but we do seem to know they didn't handle the rollover. Time is fine for me the date doesn't matter. I'm a hardware engineer and I do agree of course the GPS chip is working obviously it must know a time to work. I've driven thousands of miles using my navigation in the last few months and its right on the money.

scummins06

I have a 2010 Grand Sport. clock started working about a week ago.

bikingles

My clock started working again a few days ago but date shows Jan 2001. Is there anyway to update to proper date. If not I can live with it.

RJRSW

I have a feeling that because of all the GPS units that were having trouble from many different brands that they updated the software in the GPS sats to fix the problem that a lot of units were having.

vintagegas

If the software in the GPS sats was updated...how come most of us don't have the clocks?

corvettezman

They were updated to a different format that our radios can't see. Sort of like going from analog to digital TV per se.

vintagegas

Thank you for your answer.

I can't believe with all the intelligent people on this forum that someone has not figured a way around this problem. Hope it happens soon.