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Discussion Starter #1 (Edited)
Hello,

I went to put my top down today and the buttons that bring it down and up don't function (the other buttons, heater, DSC, etc. work fine). No lights come on...nothing. I am, however, able to get the top to go down with the remote control. I checked the corresponding fuses and they seem good.

Any ideas?

Thanks!
 

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Hello,

I went to put my top down today and the buttons that bring it down and up don't function (the other buttons, heater, DSC, etc. work fine). No lights come on...nothing. I am, however, able to get the top to go down with the remote control. I checked the corresponding fuses and they seem good.

Any ideas?

Thanks!
Seems you may have answered your own question here: The top functions but the buttons do not. I would venture a guess that they have been mashed so many times over the years that they aren't making contact or the plug to the back of them has wriggled itself loose.
 

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Discussion Starter #3
Anyone else have a suggestion. I have it a the shop and they are having trouble diagnosing. They are trying to say that it was a result of installing an aftermarket radio (Eonon D5150z). However, I told them the top worked fine after I installed the radio. The radio, however, for some reason kept resetting itself back to factory after a couple of days and so I shipped it back for a replacement.

Would the installation of the radio cause any issues with the buttons to raise and lower the top?

Thanks in advance...
 

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Anyone else have a suggestion. I have it a the shop and they are having trouble diagnosing. They are trying to say that it was a result of installing an aftermarket radio (Eonon D5150z). However, I told them the top worked fine after I installed the radio. The radio, however, for some reason kept resetting itself back to factory after a couple of days and so I shipped it back for a replacement.

Would the installation of the radio cause any issues with the buttons to raise and lower the top?

Thanks in advance...
It's a puzzler. If it worked after you installed the Head Unit and now it doesn't, I can't see how it could be the problem. I would have them test that the buttons are getting continuity.
 

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It's a puzzler. If it worked after you installed the Head Unit and now it doesn't, I can't see how it could be the problem. I would have them test that the buttons are getting continuity.
This disrespectful individual is not worth helping, please do not waste your time.
 

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I'm going to up this post as I have the same problem -

I just took out the center console buttons and tested the connections with a volt meter - both have a perfect electrical cycle. i.e. the buttons are not worn/ the problem.
There are no errors in INPA.

If we assume that the cables to the CVM are good as well (car is in perfect condition...), then that leaves us to the CVM itself. According to this pdf, that is where the buttons go to:
http://www.bmwtech.ru/pdf/e46/ST034/5 CVM and Convertible Top.pdf

A couple of questions arise:
Has anyone heard of this problem before. Searching the net, there is little to no info.
How can the top operate w/ the key fob buttons and not the buttons in the central console? I believe this was something related to the key fob going to the comfort module, which different from the CVM... Can someone more knowledge-able pitch in?



OP, did you get your problem resolved?


Also, if I get a different CVM, will it have to be reprogrammed to my specific car?
 

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Sorry to resurrect this thread, but having the same issue OP described. Not a lot of info around it. Going to try INPA and see if I get any info

Did you ever get this fixed OP?
 

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I have this same problem. The roof only operates with the key. The buttons in the car do nothing, they don't even light up.

What I have found is that if i turn the engine off and remove fuse number 46 and then put it back in I hear a bit of noise from the back like its resetting or something, I then turn the ignition on and the roof buttons work fine.
Then I will go drive for 10 - 15 mins and when i stop the buttons are not working again. To put the roof back up I have to follow the same procedure of removing and reinserting the fuse.
I have tried 3 or 4 different new fuses and it is always the same.
You have to be fairly quick after reinserting the fuse ( I tried doing it the other day while the car was on jack stands and walked from one side of the car to the other after reinserting the fuse and by the time i got there it didn't work, I had to get someone to do it for me while i waited to turn the ignition on)
I usually just sit in the driver seat and lean over to pull it out and put it back in, then after hearing the noises from the back I start the engine straight away and open/close the roof.

Hopefully someone can make sense of this and maybe know a fix ?
Thanks
 

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So I used inpa today and there were no error codes stored in the normal memory but there was one stored in the shadow memory.

112 Low voltage at clamp 30

Why it wasn't in the normal memory i don't know because the buttons in the car still do not work.

As i said previously, the roof works from the key and the buttons in the car do work for a VERY short time if i remove and reinsert fuse 46.


Something new today, while using inpa i selected the ACTIVATE button and manually activated each of the 4 or 5 valves and also the hydraulic pump. Each one made a noise and after this the buttons in the car were working. HOWEVER after unplugging the ODB and turning the car on and off the buttons were not working again.

I went back into inpa and this time selected STATUS which gave me a communication error. So i went back to the ACTIVATE section and clicked just 1 of the valve buttons, i heard a noise and so went back to the STATUS section and this time it connected just fine and the buttons in the car were also working fine again.

Its like it needs to be reset or something every single time.

After reading around forums all day again I have come to the conclusion ( GUESS ) that my CVM module ( CONVERTIBLE ROOF CONTROL MODULE ) part number 8375444 is faulty.

These i think are about £1000 new from BMW 😅 but i read that quite a few people had success replacing theirs with a used one from ebay. There seems to be a lot for sale on there that range from about £15 to £100.

I am going to order one now and I will report back once I've installed it.

It is located behind the rear left door card and the rear seats need taking out to get to it although this is not as bad as it sounds.
 

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I’d say the most difficult part is removing the panel to access the cvm. Seat is easy. I’m sure there is a video on the process.
 
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