[SwedishPolarbear]

Hi,

I recently got the black screen and no 51 fuse blown. The dealer wanted ridiculous money to find and fix the issue 😲.
My thoughts are, get the fiber loop thingy, put it on the unit on the rear aft right radio/amp and if culprit, replace with new aftermarket unit (MATCH PP 62DSP).

Does this sound like a workable plan? 🤔
Any and all advice is appreciated.

Thanks
//Polarbear

 

[Troystg]

You have a thread on this black screen so I can go read about it?



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[SwedishPolarbear]

You have a thread on this black screen so I can go read about it?



Sent from my Pixel 4a (5G) using Tapatalk

Hi, no, no thread from my side yet.

But this is what seems to have happened.
During the summer in Sweden we had some very warm days during 2020.
One day the unit did not start as normal and I thought it was due to the heat and I let it cool for the evening.
When trying to start it up the screen comes on for a few seconds before it blinks and goes black.
You can see that it sort of tries to start up the services like radio, BT or Nav, but then dies.
Upon checking the fuse, it was burnet. I put in a new one but that one blew directly indicating some kind of short circuit.

I then contacted the local VW dealer to have them do a first check on what the issue might be (I don't have a VAGCom or similar unit). This is what they came back with:

(Translated):
"There is an event stored with optical databus failed to connect. Check on fuse nbr 51, not okay. Seems to have been short circuited with ground. Recommend removal of trunk liner to be able to measure cables for further investigation."
They wanted me to agree on an extra cost of 800$ for them continue looking for the error... I said no. The first part had already costed me 200$.

So there we are.

Any advice?

//Polarbear

 

[Troystg]

1. VCDS would be cheaper.
2. Can you do any work yourself?
3. You don't know which component failed (3 for non-dynaudio system)
4. Personally I would start with a factory reset.
5. Then investigate the wiring in the back right quarter panel. Might be as simple as wire chafing.

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[SwedishPolarbear]

Thanks Troy,

I can do some work, but I am not a mechanic och electronics engineer.
I will tare down the trunk as soon as I have the optics looper and then have a look at any noticeable damage on/around the cables that I can get access to.
I am just wondering what can have chafed a cable that are not close to any moving parts Could they be damage under the carpet from the front of the car under the mats on its way to the back?
Also, if the cable is damaged, then my suggestion to replace/use a aftermarket unit will not work as it relies on the stock power and speaker cables?

//Polarbear

 

[Troystg]

" Seems to have been short circuited with ground. "

Not the optical cable shorting to ground, it is plastic. It would be a copper wire.. The connection from front to back would be the optical loop not copper so I doubt that would be the problem under carpet.

The MOST / amp box in the rear right has a wiring harness that is a goes toward the fender and has the speaker wires to the doors. Could also be a short at the door for a speaker..

VCDS would REALLY help, and will be useful for any other issue that arises.

 

[Troystg]

Also, there is the dash unit that has a fuse, the glovebox unit that has a fuse and the rear box that has a fuse.... Any of the three go out the MOST buss / ring stops..

 

[SwedishPolarbear]

hmmm, so, a blown nbr 51 fuse can be any of the 3 other units that are either faulty or have a blown fuse by them selves?

As VCDS/VAGCom is a bit further down the road, the "only" option would be to pull out each unit, check the onboard fuse, cabling, shortcut the optics and if no issue continue to the next unit?

I will do some more detailed checks of the backdoors to see if I can find any chafing or similar.

Thanks

//Polarbear

 

[Troystg]

I really don't see it as being a speaker wire in the door (or any where else for that matter) as that would just log a fault code and that speaker would be shut off.

I would look for the three component fuses and check each.

Then inspect the most / amp module in the rear.

Lastly pull the display out of the dash and check it's wires.

The radio tuner and amplifier are in the rear. The dash unit is just controls and display. The glove box is players (cd/dvd, SD x 2, Hard drive) and navigation.

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