IHU to VGM connectivity problem

[glennda5id]

2021 XC40 BEV software 5.0.5 update a few weeks prior to this issue starting.

IHU has no internet connectivity but SOS light is white and Volvo Cars app works.

I see  VGM-U105E00 error code occasioanlly.

Orbit cannot write config changes because it cant talk to the IHU, I assume communication is via VGM?

Everything else in the car works fine.

Any thoughts?

[glennda5id]

I fired up VDASH, I cannot communicate via VGM too IHU, AUD and CSD.

I did a full IHU reset, but the issue seems like its probably with the VGM since I have 3 modules that cant talk to the VGM.

[glennda5id]

I figured this out. I had originally did the TCAM reset by pulling the TCAM fuse and disconnecting the TCAM battery under the rear seat which did reset the TCAM. However I still did not internet at IHU.

I then disconnected 12v battery. Which didnt fix issue. What did work was disconneting the 12v batter and the TCAM battery as I guess the TCAM battery goes to VGM as well.

Interestingly, VGM reset from Orbit did not fix the problem either.

[glennda5id]

Okay, so it has stopped working again, after a few hours.
Looks like AUD is connected to IHU via MOST and CSD is directly connected to IHU.

So when IHU cant talk to VGM, you wil loose communication with CSD and MOST.

So could be issue with IHU or VGM I guess.