Info touchscreen and bluetooth module playing up - any ideas?

[Redtail]

Discovery 4 2011 HSE with the older Denso full sized touchscreen.

Over the past few months, the Land Rover bluetooth connection to my Android phone has been playing up. Not connecting properly, or not showing call logs, etc.
I figured it was the BT unit in the rear cargo area. I've gone in, pulled it out, checked connections and part numbers with a view to getting a secondhand replacement.

With the module removed, I started the car. All good, except the touchscreen showed just the LR logo. No info. No camera. Appeared to be screenloacked.
Turned car off. Let it sit for 10 minutes. Put the BT module back in, checked all connections as best I could.
Started it up. Touchscreen boots up. Rear camera works, 4x4 info works, phone display asks tells me I should connect (this was the original problem!).
However, the AV stays on AM radio without sound. Can't change radio band or station.
I also can't see the BOVEE\INVERY BT module for streaming via my phone.

Power it all off and decide to check fuses. Started with number 67. Pulled it out, fine. Went to put it back in. Dropped it down behind the glovebox. No probs, grab the spare 15A from the slot nearby. Drop that down the back too. (FFS! Who designed this crap???)
Read up on fuses, note that 67 is for rear entertainment. Not fitted on mine, so no probs. Slot is vacant now.

Restart car.
LR logo locked on screen.

Where do I start?
Hard reset?
New car?

Oh, and then I check my phone and see a notification from some time in the past hour "Click to connect to Land Rover". At some point the BT module has started working, and I've missed it.

[josh.huber]

I'm about to do the same, same car 2011, I've got the Cambo car play so it's not so annoying for me at the moment..I also had the BT module.

At risk of getting it wrong. The module in the rear operates on MOST, basically a series circuit. By unplugging anything you basically unplug it all.. You can get MOST bypass off eBay (I think) to rule out dead modules taking down the most. Mine has failed the same. Most works..bt doesn't.

This school holidays I was gunna pull the fridge and panels off and actually diagnose it.

[Redtail]

Cheers, Josh.

Who the bl__dy hell decided series connections were the way to go in the 21st Century!!!??? LOL

Yes, since posting, I've been reading wider. Looks like this MOST thing is the issue.
I suspect the BT unit coming back online, my phone seeing it, head unit functioning and all, was just part of the original intermittent issue.

Now I need to source a replacement BT unit or a loop.
Might try the local wreckers first for a module.

I'm also going to pull the glovebox out to recover the dropped fuses (maybe), and then I too have put back my drawer system and fridge. Apart from that, easy job!

[oldyella 76]

I find that the dropped fuses will eventually end up on the floor under the glove box. I have been known to blow a little compressed air into the area to dislodge a fallen fuse and have good success. Anyway fuses are cheap.

[BradC]

Who the bl__dy hell decided series connections were the way to go in the 21st Century!!!??? LOL

It's a token ring network and for high speed fibre optic in a car it makes perfect sense. If you break it, nothing on the network gets its "I know you have power, but here's the official wake up message" from the MOST master, so nothing on that ring works.

It is a bit of a bugger to diagnose though. Oh, and don't look at the pretty red light (or as my physics professor used to say "don't look at laser with remaining eye").

[Redtail]

It's a token ring network and for high speed fibre optic in a car it makes perfect sense. If you break it, nothing on the network gets its "I know you have power, but here's the official wake up message" from the MOST master, so nothing on that ring works.

It is a bit of a bugger to diagnose though. Oh, and don't look at the pretty red light (or as my physics professor used to say "don't look at laser with remaining eye").

I thought token ring died with IBM in the 90's? Well, there you go. Give me star topology any day.

[Redtail]

I find that the dropped fuses will eventually end up on the floor under the glove box. I have been known to blow a little compressed air into the area to dislodge a fallen fuse and have good success. Anyway fuses are cheap.

Cheap, yes. I think I'll go that way and buy a dozen. At least one of the little buggers will go in!

Is there a secret to getting them in? Patience? Body off, via a secret flap on the firewall?

[josh.huber]

Long nose pliers

[Redtail]

Long nose pliers

That's how I got into trouble. Perhaps I need to be a little more patient and careful?

Meanwhile, all I have is the nice LR logo. No other functions at the moment.
There goes my Easter weekend.

[Redtail]

It's a token ring network and for high speed fibre optic in a car it makes perfect sense. If you break it, nothing on the network gets its "I know you have power, but here's the official wake up message" from the MOST master, so nothing on that ring works.

It is a bit of a bugger to diagnose though. Oh, and don't look at the pretty red light (or as my physics professor used to say "don't look at laser with remaining eye").

I've ordered a secondhand BT module, still on its way.

In the meantime, I've checked to see if there's any red light from the cable to it. Answer is no.
Is this because it's a momentary thing on start up, and I'm missing it, or should it be constant?
BTW - the main screen won't go past the LR logo into normal mode, but I can get the unit into the "secret menu" and test things.
One of those is the MOST test, and it reports "Ring Break".

Also did a scan with the gap tool.
ACM-Audio System reports U2003-31 - Fibre optic communication bus - Frequency modulation/pulse width modulation failure - no signal (2B )

Is each error because the BT module isn't there or failed? Or do I have a broken fibre optic cable?

Frustrated.