Another e85 roof issue 😵‍💫

tug said:
Hope you get to the bottom of this, it is a very interesting thread.

Notice Martin and stuart are still exceptionally helpful to all, if anyone will get to the bottom of this they will.

Good luck, tug (y)
Click to expand...
Well........ you say that, but:

I drove down to Bracknell yesterday and spent well over 4 hours helping (or not) Steve with his zed.
Quickly diagnosed the SBSL as being a dud, but no point making that expensive swap until the roof was sorted.

Press the buttons, absolutely nothing happens. A brief list of things tried:

Swapped the relays
Swapped the CVM (control module) - and also tested it in my car to prove it worked there
Swapped the switch panel
Tried lowering the roof manually to see if it would go back up
Swapped the fuses
Swapped the GM5

Nothing worked.
INPA, Scanner 1.4 and Autophix 7900 all said they couldn't communicate with the CVM. So unable to read faults or live data.
Definitely seems to be an issue with the K-bus wire which is used by the modules to communicate with each other.
We tried rigging a wire from the K-Bus 'comb' straight to the CVM, didn't work. Then we tried the same thing from the Instrument cluster (as that tells the CVM outside air temp and vehicle speed.

I also used INPA to check the data from the Instrument cluster, and confirmed temp and speed readings were correct.

I ran out of time, with it being 2.5 hours each way for me to travel.

Where we are left is with a suspected failure in the K-Bus to the CVM. It should have a 12v 'carrier' and the module then fluctuates that (like a sine wave) to send signals out. The wire at the comb has 12v, but less than 2v at the CVM. We 'assumed' it was a direct feed from one to the other, but our rigged wire didn't work. so either that had too high a resistance, or the K-Bus routes via something else?

As I type, Steve is ripping apart the entire K-Bus wiring throughout the loom, trying to ascertain the route it takes and hopefully find it damaged somewhere.
Until that is found and repaired, we cannot move any further forward.

BTW, both @bigwinn and @Street were on Whatsapp to me throughout, trying to assist, so thanks chaps.
 
I know this isn't in the 'spirit' of this thread but....
There are times when a gallon of petrol, a match, very good insurance cover and local beauty spot is the best idea.
 
I did find a bulge in the cvm k bus wire (near offide satellite airbag module) which read 12v on 1 side of the bulge and 5v on the other.

I repaired, soldered and shrink wrapped the k bus wire and now have 12v at the cvm.....but still no roof operation or lights on the roof switches.

I've ordered a couple of code readers so will see if they're able to see the cvm now that the k bus wire to it has been repaired.

Never been so frustrated with a car issue
Seem to be going round in circles 🤬
 
I was convinced it was a k-bus issue. It could still be: we won't know that until we can see if the CVM is communicating with a code reader.
Sometimes, another module on the k-bus can cause issues, but Steve has swapped GM5, CVM, Instrument Cluster and SIM85 to no avail.
I have also taken the CVM and plugged it into my car and it worked perfectly, so we know it's not the module itself.
One of the gang suggested the roof will not move if it thinks a hard top is fitted, but NewTIS states that will only prevent the roof coming up, and this one won't go down either.
INPA can show all the various switches, sensors, etc working in real time, but so far it cannot connect, through the k-bus, to talk to the CVM.

Anyone having any brainstorms will quite possibly save this car from scrap!
 
It’s a long shot but is there another module causing the kbus issue?

Can all modules be seen on inpa (excluding the roof one)
 
bigwinn said:
It’s a long shot but is there another module causing the kbus issue?

Can all modules be seen on inpa (excluding the roof one)
Click to expand...
Yes they could. Did full scans with Autophix and Scanner 1.4, then went in deeper to each module with INPA. For example, wanted to be sure outside air temp and vehicle speed were being recorded correctly as they can prevent roof operation. Couldn't find any obvious issues.
Hopefully another scan now will be able to talk to the CVM. Then it can maybe tell us what it's problem is, or at least enable INPA to work through the live data.
 
And nothing suspect aftermarket like stereo that could be messing with the kbus? Security system?
 
bigwinn said:
And nothing suspect aftermarket like stereo that could be messing with the kbus? Security system?
Click to expand...
Steve has the car so stripped you can walk from the radiator to the roof motor!!!
I couldn't see anything untoward tbh. Definitely no gaptech thingummy.
 
Have you tried
- a complete new sensor loom swap
- swapping the round sensors on the hard top pin holes (if it thinks the hard top is in place it will prevent roof action)
- check the temp reading on the car is accuarate and isnt sub zero ?
 
Number5 said:
Have you tried
- a complete new sensor loom swap
- swapping the round sensors on the hard top pin holes (if it thinks the hard top is in place it will prevent roof action)
- check the temp reading on the car is accuarate and isnt sub zero ?
Click to expand...
@bigwinn supplied a complete new roof loom which has been installed.
Physically checked the hard top sensors but didn't replace. However, NewTIS states that this will only prevent raising of the roof, not lowering.
Used INPA to check the temperature reading sent from the Instrument Cluster. It was accurate at 9.5 degrees. Also checked the zspeed output in case it thought the car was moving.

Mr Esso and Mr Swan Vesta are on standby!
 
Just an update as I wait on the delivery of my code readers.

Took another step back at the weekend as my roof motor died. Fitted another one this evening and works as it should when hooked up to 12v.

I've learnt quite a bit whilst struggling with this cars roof. It's been easier to work with the interior completely stripped out.

It occurred to me, that, for many facing similar issues, there's not going to be many who end up stripping out the car.

I've attached the roof wiring diagram for my particular model (2003 e85 2.5l uk).

Mine has the early 2 connector cvm (convertible roof module) with a 6 pin and a 14 pin connector.

If you're having issues and want to satisfy yourself that the wiring is ok without removing everything. Try this....

Release the latching mechanism manually with an alan key. Remove the 2 connectors from the cvm. Get a piece of cable (similar in thickness to the roof motor cable). Get a couple of safety pins and connect them to each end of the wire.

Working with the 14 pin connector.
Put one end of the wire into pin 2 (red/grey-permanent live). Put the other end into pin 11 (white/blue). If the wiring is ok up to the relays and then back to the roof motor, the roof will start to lower. To raise the roof, it's pin 2 and pin 12 (red/grey and white/black).

To check the latching motor, you'll need 2 pieces of cable. The one used to check the roof motor and another with safety pin at one end and earthed to the cars body at the other.

To check the operation of the latching mechanism, first manually adjust the mechanism with an alan key so that the latch is midway.

Then put the cable with 2 safety pins between pin 2 (red/grey) and pin 1 (black/red). Then lightly touch pin 4 (black/yellow) with the pin and cable that's earthed. Then check whether that orientation opens or closes the latch.......only for a couple of seconds as you're just checking movement. You dont want to over exert it.

To get the latch to move the opposite way, use the cable with the 2 safety pins and put into pin 2 (red/grey) and pin 4 (black/yellow). Then lightly touch pin 1 (black/red) and check for movement.

My understanding is that the latching mechanism uses a live and ground so flips between cables to open or close.

I'm sure the technical guys in the group will explain it a lot better than me 😂.

This is just to check if your wiring is sound without stripping everything out.

I've had to do a deep dive into this car but maybe the testing of the 14 pin cvm connector may help others to avoid a deep dive.

My main wiring seems sound now.

I'm hoping that now that the cvm k bus wire has been repaired, that the code reader will be able to see it now.

Will update when code reader arrives and I've had a chance to look.

Thanks to all the guys who have gone out of their way to help. It's much appreciated.🙏

Special shout out to enuff_zed...top guy 👌🏻
 

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UPDATE.....

I think I may have found it.

I knew that the guts of the roof was working after "hot wiring" the cvm connector as explained above.

Got an Autophix 7910 after Martin (enuf_zed) recommended it.

Initial scan showed nothing.

Then I had a flashing red light on the roof switch and the scanner could see the cvm. The last time I had any switch lights working was when the roof last worked before the battery drain.

Erased fault codes which related to locking cowl voltage and ground issues. Think some may have been historic.

Then flashing stopped and I was back to square 1.

I then tried the switch again which flickered indicating a loose connection.

Pressed the roof button while fiddling with the cvm wires and discovered that if I squeezed the k bus repair section while pressing the switch, the roof would kick in and start to open. Closing also worked whilst squeezing the k bus repair.

Note to self....make a better job of repairing cables 😬

Can somebody please confirm.....should the roof work without the key in the ignition. Mine does but not sure if it should 🤔.

Also, tried the key in the door to see if the roof would open and close but nothing. Windows go up and down but nothing else.

Tried re scanning and the code reader still can't see the cvm....even when manually looking for it.

It saw it on that one occasion but nothing since.

Going to take this as a small step in the right direction and refit a few bits back in the car.....gm5 module, k bus comb/relay carrier, instrument cluster, light module etc etc.

Just need to book Martin back in to see if we can sort the airbag system out now.

To recap what i believe my fault was.....

I think I had a small break on the k bus wire near the offside satellite airbag module. It wasn't completely broken but was struggling along with a couple of kinks in the wiring of my roof harness.

Testing various theories meant cutting the k bus cable about 6" from the cvm.

A replacement roof harness from Bigwinn sorted that part of it but my repair of the k bus cable near the airbag module was better than my repair near the cvm.

I'm hoping that I can finally move forward.

This car has certainly pushed me to the limit 😠

Thanks for everyone's input and advice 👍🏻
 
@10stb - I think I lost you in the end there? So have you now repaired that k-bus wire again and it's working properly. You seem to say you got it working, but now it doesn't again?
If it has turned out to be the K-Bus then I'm glad I kept going on about it. I was starting to doubt myself, but what else was left?

My roof only works with ignition on.

As we have discussed, I may not be free for a little while now, but happy to help you sort the airbag issue. That at least looks like a simple case of a failed SBSL.
 
It can work with ignition out in the case of opening with the key/door lock

Which needs to be coded
 
bigwinn said:
It can work with ignition out in the case of opening with the key/door lock

Which needs to be coded
Click to expand...
I was thinking that and trying to work out if maybe the CVM is a bit confused as it seems not to work on the key in the door.

@10stb - if you at least have it working for now then either I or Stuart can probably help you use your newly-acquired Scanner 1.4 to get the coding all sorted too.
 
enuff_zed said:
@10stb - I think I lost you in the end there? So have you now repaired that k-bus wire again and it's working properly. You seem to say you got it working, but now it doesn't again?
If it has turned out to be the K-Bus then I'm glad I kept going on about it. I was starting to doubt myself, but what else was left?

My roof only works with ignition on.

As we have discussed, I may not be free for a little while now, but happy to help you sort the airbag issue. That at least looks like a simple case of a failed SBSL.
Click to expand...
Yes k bus repaired and roof working now 🤞🏼
 
Brillint news @10stb 👍🏻 Glad to see that you’re one step closer to having everything sorted, looking forward to all the stuff working and you enjoying the ride.
 
Hey Guys

Just one final update on this thread.

An hour after thinking I'd fixed it yesterday.....it stopped working again.

This time I knew where to look.

I know a guy who has a scrapper z4, so this morning I made a 5hr round trip and cut out his cvm wiring loom.

When i got home I spliced it in the boot so that it's easy access moving forward.

Roof now works as it should, switches shut down a couple of minutes after key removal and the roof/windows work as they should when manually using the key in the drivers door.

Code reader can now see the cvm.

Think it was a dodgy 14 pin cvm connector that finally gave up yesterday.

I stuck with it when every bone in my body was telling me to torch it 😩.

Thanks for all the advice and words of encouragement.

Airbag modules to do but hopefully the worst is behind me.

Cheers

Steve 😎
 
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