Clock DST functionality incorrect, thoughts?

So this has been an issue with my vehicle since I had the factory Sync 2/MFT system on board. Essentially the Daylight Savings correction for the clock is unusable in the Fall-Spring half of the year as it always stays an hour ahead when the clock is reset. Thankfully I don’t reset it often enough to be a bother. Just reset to GPS, tick the hour back one, and leave it.

That said, I had hoped to see this resolved when I updated to Sync 3 especially being on top of the most recent updates. However that does not seem to be the case and I’m still stuck seeing the clock be an hour ahead after resetting it.

One thing of note is the BodyCM is the master clock in my vehicle. Would I be correct in thinking that the actual DST calculation/functionality is in the BodyCM instead of the APIM? And thus probably will require a BodyCM update to fix it, if such a fix has been implemented?

I don’t really know, but out of curiosity I searched As-Built Database - CyanLabs , and there are some parameters for the clock and clock master.

Do you have forscan? What values do you have?

I would say that seems likely, i’m pretty sure other people have similar issues on this forum also. the BCM will probably be the cause if that is what the master is set to.

Per the AsBuilt DB, this is what the Clock Master related bits are set to:

7D0-01-01: ##XX-####-####
28=EP Off, EPT 30mins, CM BCM (C1MCA and CGEA 1.3), MC Disabled, SWC Not Available

Sync 2 support for DST was removed in version 3.6.2, or thereabouts.

Ford Master Clock.pdf (298.8 KB)

Offset = UTC time – current displayed time
This offset value is used every time the slave module powers up. Upon powering up, the offset is added to the UTC time provided by the GPSM/satellite antenna and then compared to the clock that the slave module internally tracks.

When you upgraded to Sync 3 from Sync 2, did you disconnect the GPSM?

I have a massive writeup from Ford on this. Explains it really well to.

Type A - The SYNC Module (APIM) for vehicles equipped with SYNC Gen 2 or SYNC 3 is the clock
master. If the vehicle is equipped with SYNC Gen 1, the front control/display interface module (FCDIM) is the clock master.

Type B - The body control module (BCM) is the clock master. The APIM and FCDIM are slave modules. Here are some basics on it.

Type C – These vehicles follow the same rules as the Type B architecture type vehicles.
Older vehicles and vehicles that are not listed in Figure 1, the audio control module (ACM) is the clock master. For vehicles equipped with SYNC Gen 2 or SYNC 3, the clock master can be determined through APIM Bezel Diagnostics > APIM Diagnostics > Configuration Status.

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I did not. So far it has not interfered with the new GPS source on the Sync 3 APIM as reported by some with other vehicles. And as far as I am aware, a couple of EV related functions (Such as EV+ and Value Charging) still rely on the GPSM.

Correct. Just like the compass in the IPC in my 2015 F-150. Disconnecting the GPSM should not be done unless it interferes…good you didn’t.

I have read that this is a documented issue with the Sync system in general, but have seen no hard solutions for it. I suggest starting with an APIM and BCM resets, but I figure you’ve probably been there already. (Resetting the BCM will cause a circus show…) Also, reload the APIM asbuilt entirely and perform a master reset.

Other than the clock settings in the APIM at 7D0-01-01, I have not seen any options for DST other than the DST on/off option in the APIM clock settings.

7D0-01-01: ##XX-####-####
28=EP Off, EPT 30mins, CM BCM (C1MCA and CGEA 1.3), MC Disabled, SWC Not Available
28 would be EP ON…A8 would be EP OFF.
Looks like there is a typo…I’ll be fixing it but waiting on the server maintenance thing to be over (or fixed) so I don’t nuke something…

As for the resets, I do think the BCM had one recently when I had the PAM firmware updated as it did the whole ‘put all the modules into programming mode and reset after’. It did cause the whole circus show for sure. APIM’s definitely been reset a few times since as well including a full master reset on the last update. However I haven’t done so since then.

This is once again just an oddity and not a huge issue but I definitely appreciate all the useful information provided. So the TL;DR I’m seeing is the BCM just holds the UTC time (on my particular vehicle type) but the APIM’s still responsible for the time zone and DST adjustments and it is just a continuing bug carried over from Sync 2/MFT.

Just FYI, I show a 13 CMax as a Type C Clock Master Architecture Type. This means that your Clock master is the BCM.

The body control module (BCM) is the clock master. The APIM and FCDIM are slave modules.
• GPSM/Antenna

  • Receives the UTC Data
  • Sends the UTC data to APIM
    • APIM
  • Receives UTC data
  • Sends clock change request
    • BCM (Clock Master)
  • Receives clock change request
  • Sends clock data to APIM and IPC
    • IPC
  • Displays clock data sent from BCM

For vehicles with navigation - The APIM (slave module) is still responsible for reading the GPS data from the GPSM/satellite antenna, applying the appropriate time zone offset, and comparing that time to the current tracked time provided by the BCM (clock master). As a slave module, the APIM will not automatically update the time displayed on its own. The slave module will request a time change from the clock master. The clock master then sent a request to the slave modules to update the displays.

For vehicles without navigation - The slave module will still calculate the offset. It will also use this offset value and the time provided by the GPSM/satellite antenna to compare with the current time value from the clock master. If the times do not match, the slave module will send a time change request to the clock master instead of instantly updating. The clock master will then send the request to have the displays updated accordingly.

Offset = UTC time – current displayed time.

This offset value is used every time the slave module powers up. Upon powering up, the offset is added to the UTC time provided by the GPSM/satellite antenna and then compared to the clock that the slave module internally tracks.

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