Ring Loop MOST issue

[SwissXC90]

Originally Posted by Elsimo

I have a 2012 XC 90 exc with exactly the same symptoms as you describe. I have been able to get the radio/cd player working correctly by unplugging the MOST fibre optic cable from rear of the satnav unit under the passenger seat and plugging it into a MOST loop, thus removing the Satnav from the system.
On checking the Satnav it appears to be receiving power ok as I can see lights in the front of the unit and when I turn the ignition on there is a red light emitting from the Most socket on the rear of the unit under the seat.

Have you put the sat nav into diagnostic mode and read off the diagnostic info?

You do not need any tools for this.
And the diagnostic info tells you a lot.

[Elsimo]

Hi Swiss xc90.
No, the unit is to all intents shut down, I cannot get it to light-up at all, as I said the only action I can get out of it is to wind the dash display up manually then as soon as I reconnect the power it immediately powers down. I have tried pumping the back and enter buttons on both the steering wheel and the remote control but it refuses to respond.

[SwissXC90]

That's a shame. If you really want the nav to work, you need to determine if the screen or the nav unit itself is at fault

Just because the screen motors down again, doesn't mean that the screen is fully functional.

Note that nav units are coded to the car and a replacement second hand nav will need the flash memory overwritten with your flash memory contents - something only an electronics expert can do.

[Dashing]

I have a Volvo xc60 2016. My infotainment system freezes and restarts every two to three minutes. I checked the MOST fibre cable leading into the amp. The cable gives a red light but there is no red light coming from the amp.

Dice is giving this error. ICM-U1A1587 Incomplete MOST Ring Reported By IHU - Bus
Signal / Message Failures - Missing message

Your help is extremely appreciated!

[SwissXC90]

Originally Posted by Dashing

I have a Volvo xc60 2016. My infotainment system freezes and restarts every two to three minutes. I checked the MOST fibre cable leading into the amp. The cable gives a red light but there is no red light coming from the amp.

Dice is giving this error. ICM-U1A1587 Incomplete MOST Ring Reported By IHU - Bus
Signal / Message Failures - Missing message

Your help is extremely appreciated!

Sounds like you identified where the issue is. Anyway, VIDA gives a very good most ring bus diagnostic description to find the faulty device or broken cable, just follow what is written in vida.

[Dashing]

Thank you for your swift response I really appreciate it. I don’t have Vida or DICE. I took it to a Volvo dealership and they gave me the code. They want me to book in the car for a further 2 days to “diagnose” it. I must pay them a fee to diagnose it and only afterwards they will “quote” me to fix it. So basically an arm and a leg.

I’m thinking of taking out the amp out to inspect. Hoping it is really something simple.

[SwissXC90]

Originally Posted by Dashing

Thank you for your swift response I really appreciate it. I don’t have Vida or DICE. I took it to a Volvo dealership and they gave me the code. They want me to book in the car for a further 2 days to “diagnose” it. I must pay them a fee to diagnose it and only afterwards they will “quote” me to fix it. So basically an arm and a leg.

I’m thinking of taking out the amp out to inspect. Hoping it is really something simple.

if you have no diagnostic tools you are stuck.

VIDA tells you how to do a ring break diagnosis. You can also temporarily bridge the fiber optic line of a suspect bad device to determine if the ring comes back up.

I suggest asking on this forum for anyone with VIDA who is located close to you. I'd happily help if you come to my house, I live in the original CrossCountry, in the alps in the middle of Europe

[Dashing]

Thank you so much. I really appreciate the assistance.

I stay in South Africa, so sounds like an amazing road trip that requires a few ferries - see you in a week or two lol.

I’m hoping I can get access to the diagnosis tools. Will keep asking around. I have a good feeling that the issues is at the amp because I don’t see that fibre light coming out from it.