I see that some are looking to find an optical loop connector. I suggest typing 'optical fiber loop connector' into the search box at your favourite China online shopping centre. There are hundreds there, and some of them must be compatible. Priced around $NZ 5.00. Other cables must be available too.

Pete M

 

With apologies to MeatBag for plagiarising his diagram, would this work to cut out everything after the AMP, please?

 

It looks like it is just a "daisy chain" of sequential connections, so apart from a bunch of modules no longer being present and chatting to each other, there is probably no harm in trying to bypass them EsRay.
At least the optical plug should be compatible to dock into the desired target unit.
No doubt the car would report the absence of hardware if you scanned it, but hopefully the general functionality from the head unit to the amp will still be logically present.

 

Okay I have removed all 4 boxes, successfully re-plumbed the D2B and restored my radios audio. However, I still have no function at my rear entertainment module (although it is backlit) and I now have Ext 50, 51 & Ext C1 constantly on my (small screen) climate control readout?

Anyone know which of the numerous fuses linked to this area is for the rear entertainment module, please?

I have a horrible suspicion that (for some absurd reason) I am going to have to re-plumb the (entirely useless) NAV unit back in? What think you, please?

Please could someone save me from myself?

 

The two supply lines to the rear multi media control panel appear to be via F20 and F30 of passenger distribution fuse box.
It does make some sense that for it have any logical status display it might need some video feed via the AV selector module which might as you suggest come from the Nav unit.
My lesser appointed XJ8 does not have the rear entertainment options, so I can't test that theory for you unfortunately.

 

Thanks Mark,
The rear entertainment center does appear to have a D2B connection numbered RC5; I just have no idea which box it goes to in the boot (if any)?
However, since my problem was a failed CDC, logic suggests that if it is to be connected to anything video-like in the boot, it may as well be the Nav unit, so I will just have to try re-plumbing that into the loop and see!

 

Hi EsRay,

I've taken a closer look at the linking and plug assignments of the D2B schematic (inserted below).
Looks like there is a specific order that each module is 'daisy chained' in this conglomerate (as listed in the side notes of the picture inserted below).
Starting from the Audio head unit it then goes....CD Auto changer | Cellular module | Voice Activation module | Multimedia control panel (rear seat unit) | Nav Unit then finally the Power Amp, before going back to the head unit to complete the loop.

As some cars will not have all modules installed (depending on buyers option preferences), the D2B configuration may vary as well as what cables are present.

Depending on which modules you are wishing to eliminate, you will probably have to link between 1 and 2 of the appropriate plug to preserve the loop and relative sequence of devices, bearing in mind that the missing module will no longer report on wake_up which may have other knock on effects but certainly report as missing in the diagnostics.
You can't just unplug DB6 from the Nav unit and put it in the amplifier instead of DB7, as the return of DB7 is back to the head unit.

 

Thanks Mark, I looked at that, but you have just made some sense of it for me! Just to clarify, are the inputs shown on the right of the diagram and the returns to the left, or are there inputs and returns on both sides, please?

My objective is to retain the AMP and Multimedia Control Panel (MCP). So, (please correct me if I'm wrong) what you are saying is that if I want to eliminate a failed module (in my case the CDC), then just use a loop on its plug. If I disconnect anything in the sequence, it destroys the whole daisy-chain (including my MCP)? If one module fails, you lose the lot?!

Incidentally, my radio audio returned when I plugged NAV DB06 into the loom and I got rid of the 50, 51, C1 business on my small LCD just by plugging in all of the electrical connectors to the modules, without connecting the D2B's.

I am really having fun with this; in addition to all of this, my screen is still coming on when it feels like it; no screen in the morning, then screen later in the day; checked grounds are fine.

 

Sorry for the tardy response....yesterday got a bit hectic at my end ;-)

Think of this more as serial data, so it comes in on pin 2 of each of those 2-way plugs and then carries on to the next module by exiting via pin 1.
Hence if you want to keep the daisy chaining somewhat complete, you probably have to either leave the module in or find a suitable jumper that will link pins 1 and 2 together to allow the communications to continue to flow around.
The larger multi-way connectors to each module carry a 'Wake Up' signal (shown as the O inside a triangle in the schematic - signifying an output signal) back to the network to confirm that the respective modules are powered up and present.

 

Thanks Mark,
When you eventually retire, you find out how much happier you were when you were busy even though life was more hectic!

So, the female one of these plugged into the CDC connector: Tiardey 2Pcs Most Fiber Optic Loop Male & Female Connector Kit,Diagnostic Device Tool Navigation Systems Female/Male Adapter: Buy Online at Best Price in UAE - Amazon.ae

 

Which explains why I got my radio audio back by reconnecting the electrics to the modules...

 

I haven't taken a close look at those connectors, only been into my Nav unit once when I first got the car so don't recall the plug format.
But if the wiring loom is fitted off with male optical plugs, then yes, the female loop connector will hopefully bridge the comms through to the next physical device.

 

Thanks Mark,
Be okay, my order gives me both male and female plugs; I will let you know which is required in case it becomes useful to you in the future.

 

Maybe this will help? Jaguar has a chart of part numbers showing which FO cable is needed depending on the cars options? As was posted above this is a daisy chain and things must be in the correct order for it to work.





I used this when I added options to an XJ I was working on.

Attached are some instructions that include how to splice the FO cables themselves. This can be useful if you don't want to buy additional cables or if you just enjoy a DIY repair.
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Hello, i tried to swap the two fiber optic cables that was suggested in this post but i still have got no sound. I have tried my amp in another jaguar and that worked great. So the amp is fine aswell.. i’m thinking that it may be the optic cable that goes to the front but i’m not sure. My father did a lot of welding from under the car to pass the mot. And he said that the audio worked great before the welding job. What do you guys think? I also did try the network test but i get no response at all. Hope you can help me.