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Something weird happened today. I was driving the Volvo and noticed that the clock displayed in the upper right of the screen was behind by about an hour and a half. I later calculated it as 94 minutes behind the actual time. It had always been accurate before. When I got home I checked the settings. Everything looked right except for the time itself. The time zone was right. It showed automatic network time as the source. I checked with Google Assistant which told me the correct time. I took it off automatic and set it to the correct time manually.

This is no big deal, of course, but what's troubling is how and why it got off by that amount. It should be getting the time continuously from "the network" (cell phone system connection, I assume). My phone displayed the correct time. It just erodes my confidence in the whole infotainment system, and there wasn't much confidence to start with. It's also an odd amount, not consistent with, say, Daylight Savings starting. The car was never without power and didn't charge that amount of time lately. Does anyone have an explanation?
 

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The correct clock time is essential for GPS and internet to work. If it is off, GPS cannot get a fix and cell tower handoffs will not occur.

It can occur from a power issue, GPS system failure, or modem problem. It is not a minor glitch or issue.

If it recurs I would not be surprised if there are multiple app problems.
 

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While I won't dispute the overall value of having the correct time, you can't include GPS in your list of affected services. The GPS signal actually INCLUDES the current time, and all necessary GPS calculations can occur without an external time source.
 

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I don’t know, I have had GPS cars for years and never had one lose time on the clock.
 

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While I won't dispute the overall value of having the correct time, you can't include GPS in your list of affected services. The GPS signal actually INCLUDES the current time, and all necessary GPS calculations can occur without an external time source.
You are correct. However, I believe, and I may be wrong, that if the clock is set to auto, it utilizes the GPS signal, or the chip information, to get the displayed time. As such, if the GPS sync is off due to power disruption or signal failure, the clock and multiple time sensitive systems will fail to work.

I may be wrong in the assumption that the GPS sync and the displayed clock are interconnected. GPS does not need an external clock...but the external clock may be connected to the GPS chip.

Volvo make it unclear what signal is used to set the clock when "auto" is chosen.

Automatic time for cars with GPS
If your car is equipped with navigation system then you have the option to select Auto Time. The time zone is then adjusted automatically depending on where the car is located. For a certain type of navigation system, the current location (country) must also be set in order to obtain the correct time zone. If Auto Time is not selected then time and date are adjusted using the up or down arrows on the touch screen.
 

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Volvo make it unclear what signal is used to set the clock when "auto" is chosen.
It's just my guess, but since (a) GPS time does not include time zone; (b) the mobile network does provide time zone; (c) Android has cell phone behavior in it's DNA; AAOS most likely relies on the mobile network for date/time.

Therefore it's certainly possible that a problem with the LTE connection could allow the infotainment date/time to drift. However 94 minutes drift is huge, and suggests a poor on-board clock. It should be able to maintain a reasonable approximation of the current time for weeks, unless power is interrupted.

(FWIW - I spent the final 15 years of my career working on Linux-based embedded systems and tangled often with the issue of keeping the system clock up-to-date.)
 
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