Here we go again...twice every year, DST threads appear, and a few minutes later, while driving in areas with ATT cell coverage (the service GM/On* use), the clock adjusts itself. I have been through about 10 such time changes, and a number of time zone changes while traveling and the clock always (eventually) adjusts to local time. I have never paid a penny for On* service.

 

Real-world example of a term often used with distributed databases: eventual consistency. Yes, that's real...

 

We should all call in the day of time change, everytime, hopefully it gets GM to fix it... whatever the issue is... if I turn my phone on after time change, it is reflected right away, why not the car?!?

 

Starting in the early 1960s the telephone system has used a time division multiplexing system that is highly dependent on both ends having exactly the same time. Because of this ATT had some of the most accurate clocks in the world and a complex and expensive system for distributing time. All of this is baked into the cell phone system. As soon as your phone connects to a tower it knows the time to within microseconds.

Almost everything else is dependent on Network Time Protocol. NTP has to work on the internet which has much poorer predictability. Your phone's time is always better than your computer's.

In any case you need some kind of connection to learn the time. And I think after the last time Congress changed the rule most device manufacturers gave up on storing DST information in the device.

 

Hmmm... for whatever reasons, the DST worked on mine. I think I drove enough so that OnStar be able to communicate with its network and got the time right.

 

I just went out in the garage to check the clock. The last time the car was driven was Friday. The clock was not only still an hour behind, it was two minutes slow, which tells me it is running off the junk internal clock. I reset it manually, and then put it back on auto-cell. I am not worried in the least. I know it will wake up eventually.

 

I tried leaving it on auto-cell. No OnStar. It never updated. Easy enough to take the opportunity to correct the minutes (yes, it drifts) and turn DST on or off manually.

 

DST changed without my involvement and I don't have a data plan.

 

Depending on the parking situation, there may be variable signal quality for cell or GPS (or both) on the Bolt. For example, some owners have reported problems setting their home location while inside their garage, and instead set the home location outside, some distance from home. The Bolt may also need to be "awake" for some period of time for the time sync to occur.

It's a poor implementation if it doesn't update in a reasonable amount of time, but there may be other trade-offs (more frequent automatic "wake-up" periods may drain more of the 12V battery, for something that only occurs twice a year...).