BCU Repair or Replace?

I see a few BCU refurbishing services advertised? Is it worth it? It better to try another used unit?

Also, am I missing something about the EKA code? Isn’t the point of it that it unlocks the immobiliser?

Better replace the fusebox too just to be ruled out

Ok thanks.
What is the exact nature of the fusebox failure? Is it simple soldering dry joints or something more?

Naki kouyioumtzis said:

Is it simple soldering dry joints or something more?

Click to expand...

It can be a simple soldering job or it can be something more as well .... to find out you'll have to fit a known good one first to have the confirmation of the fault then investigate

Ok. you may recall I tried soldering the first BCU too, and it seemed to fixed the issue for a few days, then the immobiliser failed completely, which was a bit surprising.

I work on 80s/90s Jaguar XJ a lot and as standard I solder the Fuseboxes on those without a problem. So I was hoping it would be as simple as that. But maybe not?

It may be simple as that or not but you have to be sure which one is the faulty unit...if you fiddled with the BCU then it was OK for a while it might be that... but it can be IDM failure too and there's no way to know what to check untill it's not confirmed 100% also if it's a chip failure you can be the god of all jag fuseboxes and not see anything... the interior fusebox called IDM(intelligent driver module) is a very complex unit and actually the IDM is managed by a chip

sierrafery said:

It can be a simple soldering job or it can be something more as well .... to find out you'll have to fit a known good one first to have the confirmation of the fault then investigate

Click to expand...

Ok.
I have ordered another BCU today.
But, to my surprise, the car decided to start today! Even though the immobiliser was seemingly locked out yesterday.
I just thought I would try mum luck, and what do you know.
So now it starts again fine. The Flashing B warning is intermittently showing though.
does this perhaps indicate a poor plug connection. Or more likely a dry joint, again?

Ok. I only mentioned about Jag fuseboxes, as those are a simple resoldering fix. No dead components. I was hoping it could be as simple as that, but maybe not.
I have had this Disco 2 for 3 years now, and like all cars it’s a never ending learning curve. The only way to learn is as each problem presents itself. I think I have tackled a good number of the typical D2 issues to date. Though no doubt there’s more around the next corner.....

Ok, so here’s the latest instalment of the saga.
There’s definitely an additional electrical problem.
For a start, I went over to the car to find the battery completely dead. It never had any battery drain issues before, even after weeks unused. The multimeter read 0.06v!
I replaced the battery with another full charged, and to my surprise, the dash lights came on immediately, without the key even in the ignition!
I had ordered another replacement BCU anyhow, but it’s looking like that may not be the fault after all? Or not anymore?
The car is starting, still with the flashing B, and M&S lights. The key will not shut the car off. Even disconnecting the battery did not turn the engine off. I had to unplug the inertia switch to turn the engine off.

Am I to assume this is the fusebox short circuit, causing this particular issue?
It looks like the next thing on my list?

It was a choice thing from the beginning...as the BCU is ruled out the IDM remains the suspect

Yes indeed.
It’s on the list this week.
I think I was just quite surprised at the odd symptoms displayed. I have never see a car that runs even with the key removed.

I finally got around to opening up The fusebox. Predictably there was water damage. I as cleaned up the corrosion and resoldered all the joins as best I could.
despite the corrosion, the tracks seem to be intact.
The car is running again now and not to displaying any faults. Though I am slightly sceptical it will last long term. I will get a spare fusebox ready!
The IDM chip appears uncorroded/ OK?

Well done... a least now you know for sure

Great troubleshooting.

It’s still possible there’s corrosion/ issues between the two boards/ PCB’s but I don’t want to split them. It’s more trouble than it’s worth. Hopefully a back up spare will be on hand soon just in case.

This weekend is scheduled in to fix the leaking sun roof once and all. I am sure that’s the source of all this trouble to begin with. I have known it’s been leaking for about 2 years, but it slipped down the priority list until now. Ho hum....

plus the MOT is booked for Monday.

Just choose the spare as to be removed from the same MY like yours: facelift or not cos they are not the 100% same circuit wise

Hello all

I have been reading through this with interest as had been having warning lamp issues for a few months now. First noticed something about 9 month ago after starting up; trac cont,abs & suspension lights remaining on , switch off & restart all ok This would happen once on 4-6 week cycle so was only considered a querk.
As part of a long drawn out investigation chasing a leak or several (as once 1 found & cured a few month of dryness would follow) I had removed driver footwell carpet to dry (again ) and the trim panel in front of drivers door . One day during a heavy driven rain I found a continious drip coming down from the area about fusebox .
It was after this that issues started to show. First noticed was front intermittent wiper operation and wipe part of screen wash would not work , then next morning I couldnt open car only interior lamp come on when fob pressed & key done nothing. Took other car to work & got new battery for fob, that evening fob opens & locks car several times in sucession, so thats a result untill next morning car will not unlock & I do not know the emergency code. End result car sits for 4 days while I consider which window to replace & having found 1 on ebay I come home that evening to purchase however by some stroke of luck car opens ( never to be locked again untill this is resolved ) I cure leak at the weekend windscreen o/s bottom corner 2" x 1/4" corrosion hole.
I now find several things not working wipers as above rear windows central locking from dash switch rear wash wipe. These issues would dissapear after approx 30 mins running with max heat to screen & footwell however that only lasted a week or so , now the blue main beam indicator on display and the indicators on the body also not playing. I have discovered that all items do work when wipers are on speed 1 or 2.
I have changed the fusebox for a 2nd hand "all working prior to breaking" but everything just the same, my own fuse box appears very clean with little sign of green corrosion at all. So I am now about to target the bcu to see what condition it is in.
I see there are a few on ebay but they would need to be programmed & I do not have the gear to do it
If necessary can the bcu & fusebox be tested repaired and refitted without having to be reprogrammed ?

any suggestions for anyone who can provide this service appreciated or where can I purchase the nanocom or hawkeye required

Regards Archie

When I was working through the issues, I did see outfits advertising BCU repair. Though I didn’t note them down, so I cannot recommend any specific. what I would say, virtually everyone who had these cars says you can’t run them long term without a Nanocom or Hawkeye. Sooner or later you will need to use one on your car, I put it off as long as I could, but I took the plunge eventually. If you plan to keep the car, it’s well worth having. As there will be another time. Even if you sell the car, used Nanocoms will still hold their value. So you can sell it on too.
you can order Nanocom through their official website, but the ordering process was oddly very long winded. So I bought through eBay in the end with a couple of clicks. It arrived within 3 days from Cyprus (yes really!), by DHL.
Assuming you have a TD5.
They do different versions for P38/ or the V8 models.
https://www.ebay.co.uk/itm/231561378000

you can try reflowing the soldering on your BCU too. There’s not much to loose? Though a spare will be useful too.

try one of these https://www.ebay.co.uk/itm/Discover...ld-or-supply-Dealer-recommended-/133115857675 , or https://callrova.com/land-rover-discovery-2/