Electrical wizard needed! I'm stuck! NOW SOLVED

A long and complicated tale:

E85 2.5i. Unfortunately the battery was left to go flat for about a week.
Recharged and tested, all seems good.

Initial problems..........
No wipers, no lock or unlock, windows won't go up or down, lights work ok, but no indications on the dash and no dash lighting. Airbag light on the dash. Interior light comes on when you open the door but won't go off again.

Scanner 1.4 can only see DME, ABS, LEW and IKE.
IKE shows 3 codes - 87(135) Body Bus (k-bus), BE(190) Data-filing difference to central light module (LCM), 20(032) Airbag lamp)
Codes reset but cycle the ignition and they all come back.

Fitted a replacement Star 12Low GM5.
Now the windows work ok BUT only when one of the doors is open! Close the doors and nothing happens. (At least now it is waterproof)

Swapped the battery from my car and the problems were the same.
Radio says 'disabled' on the screen. Reading that this has the potential to cause k-bus issues I unplugged it. No change.
If you sit inside the car with the doors shut you can lock and unlock from the central button, but the key does nothing.

From outside the car you can lock and unlock manually with the key in the lock.
If you lock it like this then the interior light does go out ok.

If you unlock it with the key in the lock and hold the key over the windows both go down.
If you then lock it by that method and hold the key over then ONLY the passenger window goes back up.

I am no electrician and have only my google fall-back mode to rely on.
I am finding lots of similar issues and mostly it seems to be one of the modules connected to the k-bus causing the issue.
The only option seems to be to unplug one wire at a time from the k-bus connector and see which one lets everything work again.

Where is this k-bus connector? Is it a relatively simple, slow and steady process of elimination?
Anyone encountered it before and got any tips?

At this point I'm baffled tbh.

According to the WDS there's a kbus comb in the passenger footwell to the right of the two relays there. Should do a majority of modules (basing this on the fact the LKM hangs off it.)

Wires are white with red and grey stripe (WS/RT/GE). Pull them one by one and see what works.

smorris_12 said:

According to the WDS there's a kbus comb in the passenger footwell to the right of the two relays there. Should do a majority of modules (basing this on the fact the LKM hangs off it.)

Wires are white with red and grey stripe (WS/RT/GE). Pull them one by one and see what works.

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Good starting point thank you.
Are all the wires the same colour? Just wondering how (assuming it works) I then figure out which system I've disconnected.
I guess checking the codes again should narrow that down.

All kbus lines are the same colour. Useful for identifying the kbus lines, less useful for identifying a kbus line!

I suppose, if you pull one and everything comes back to life, then it's a trial and error with INPA (or whatever) to talk to things and see what doesn't respond. Modules hanging off the main X10116 comb:

Instrument cluster
PDC
Convertible top
Safety and information module (new one on me! Behind the seats somewhere.)
Rain/headlight sensor
Heater controls
LKM
Centre console switch centre (button panel for roof, DTC etc)
GM5
EWS
Drivers seat memory
Clock sping

And, having typed all that, that seems to be pre-facelift. Post-Jan 06 has two combs (X10116 as before and X10466, location unknown in my copy of the WDS) with the modules split between them. It also adds the Crash Safety Module (same place as the safety and information module.)

FWIW, my money's on the instrument cluster since so much seems to be playing up. It seems to act as a master on the kbus.

smorris_12 said:

All kbus lines are the same colour. Useful for identifying the kbus lines, less useful for identifying a kbus line!

I suppose, if you pull one and everything comes back to life, then it's a trial and error with INPA (or whatever) to talk to things and see what doesn't respond. Modules hanging off the main X10116 comb:

Instrument cluster
PDC
Convertible top
Safety and information module (new one on me! Behind the seats somewhere.)
Rain/headlight sensor
Heater controls
LKM
Centre console switch centre (button panel for roof, DTC etc)
GM5
EWS
Drivers seat memory
Clock sping

And, having typed all that, that seems to be pre-facelift. Post-Jan 06 has two combs (X10116 as before and X10466, location unknown in my copy of the WDS) with the modules split between them. It also adds the Crash Safety Module (same place as the safety and information module.)

FWIW, my money's on the instrument cluster since so much seems to be playing up. It seems to act as a master on the kbus.

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Cheers Scott,
Luckily a pre-facelift so only one to look at.
She's going to drop the car off at mine some time in the next few days and I'll work my way through it.

Good luck!

smorris_12 said:

Good luck!

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Definitely another new learning curve for me that's for sure.
I'll be sure to feedback stuff as I work through it.

You did code the new gm5 module to the car?

Haro said:

You did code the new gm5 module to the car?

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Not needed to make it work.
As long as its a compatible model, the coding is only for the extra stuff you usually do with Carly etc.

You sure, had to code the ones I've done or had some odd things. Always copied old ncs file and wrote that to the new one. There's other ways, you can write a blank file if you haven't the original and apparently it will then force the new module to "learn" as well. It's worth a try before checking wires, etc.

Haro said:

You sure, had to code the ones I've done or had some odd things. Always copied old ncs file and wrote that to the new one. There's other ways, you can write a blank file if you haven't the original and apparently it will then force the new module to "learn" as well. It's worth a try before checking wires, etc.

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I’ve spoken to several people who have swapped with no coding needed. Plus, what are the chances of the replacement one having exactly the same catalogue of faults?

Going by your description it seemed the windows partially worked after changing. Anyway, I was just trying to help, good luck.

Haro said:

Going by your description it seemed the windows partially worked after changing. Anyway, I was just trying to help, good luck.

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Yes I’m not discounting anything at all. Apologies if it sounded dismissive.
The owner has decided to speak to an auto electrician first. Obviously I didn’t inspire her :tumbleweed:
We kept the original GM5 as well in case it wasn’t the issue at all.

Well after a long saga I thought I'd pop back and update on this fiasco!

Part 1.
The car went to a very well known 'specialist' in North Norfolk. They had it a couple of days and worked their way round all the modules on the k-bus circuit. Sure enough it was the centre airbag module, plug and socket full of some kind of congealed gunge.
They suggested a new module (£655+VAT) from BMW and also replacing the plug.
Instead of this, the usual gang rallied round and [ref]umfaan[/ref] sent over a compatible module and a length of loom with the plug on it.
This was duly fitted by said 'specialist'. They then contacted the owner to say it wouldn't work as it said it had the wrong VIN in. That sounded a bit odd, so the owner (as suggested by [ref]Street[/ref]) asked what software they were using. NCSExpert. When asked why they didn't use WinKFP the answer was "What's that?". :?
They then told her that if she did what they said the first time and bought a brand new module it would not only fix the airbag light, but was the reason the key fobs didn't work and the roof wouldn't open either.
I persuaded her to run for the hills!

Up to this point they had 'done her a favour' by only charging £530.
To sort the rest, including the new module would be another £1100.

Part 2.
The car arrived on my drive.
I refitted the original GM5, paired the key to it, and that worked fine. [ref]Haro[/ref], your earlier query about coding the GM5 may carry some weight as although the problems hardly seemed to change, I wonder now if I didn't pair the key correctly the first time around? Though the key fob wasn't at that point working on the original GM5 it may simply have needed pairing again, but the other symptoms blinded me to that? Who knows?
I relocated the roof motor and after emptying out half a pint of water I got that working as well.
Then came the faff with the airbag module. Great credit is due to [ref]Street[/ref], who remotely linked to my laptop on his birthday and spent hours trying to solve the problem.
Eventually we gave up and decided it had to be a duff module, or the 'specialist' had toasted it when trying to code it himself.
The car went home with everything else sorted while we searched for another module.

(I wonder what the 'specialist' would have done when the replacement module did not fix the other unconnected faults?)

Part 3.
The car came back to me on Sunday morning, with a compatible module ready to fit.
Beside it in the box was the loom section that [ref]umfaan[/ref] had sent, not used! Alarm bells started to ring.
I got access to the module in the car and unplugged it with the plan being to pull the plugs up and slave in the new module before I got too deep into dismantling stuff.
This is what I found!



The plug was completely beyond saving and I had to destroy it to pull the pins out. Even then I found the pins were full of the same gunk.
I had to bite the bullet and splice the new plug and loom in. Not my preferred option but all that was left open to me by that point.

After a few false starts and lots of Whatsapp help from [ref]street[/ref] and [ref]bigwinn[/ref] I finally got the airbag light to go off (using the correct software. :wink: )

The car is all back together and waiting for its happy owner to collect it.
Her costs so far are £100 for two replacement modules, one of which she may not even have needed.
The photos and physical evidence are going with her to visit this 'specialist' in Coltishall (oops! hope that hasn't given it away :roll: ) and at the very least I think she should get £50 back for the extra module she bought.

Firstly, the 'specialist' did indeed find the problem but from then on they were a complete mockery!
How on earth they thought the airbag module would stop the key working or the roof motoring I don't know.
Why did they explicitly tell her that the plug was full of crap and then quite blatantly refit it without even any attempt to clean it!
When it didn't work, did they not have even a niggling doubt about that plug?

The sad thing is that this place had a really good reputation but it seems one member of the staff has changed (the one with the electrical/software responsibilities) and its all going downhill.
I'm hoping that this may wake up the boss in time.

Car mechanics (and I use the term intentionally, given how job titles get talked up these days) have no f'in clue about electronics, given that such things have been integral for nearly 30 years. Even the most basic "is the wire cut in two?" seems to be beyond them. And, as far as I can tell, they show no willingness to learn either.

Good result!

Glad you got it sorted, hard to see but it looks a bit like water damage. If it has a low short it heats the plastic making it "bleed" so to speak. Everyday's a school day with cars!

Haro said:

Glad you got it sorted, hard to see but it looks a bit like water damage. If it has a low short it heats the plastic making it "bleed" so to speak. Everyday's a school day with cars!

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This looks like some kind of sugary drink was balanced on the open storage door and spilt. What a mess!