Hi all!

I have quite a specific problem which i have been postponing for about three years now. I have this key less go fob for my E55 which doesn’t work at the moment. This is because it was damaged by a previous owner and was never fixed properly. 2 small components are missing from the circuit board and i’d like to imagine that this will fix my problem. Or at least bring me closer to a functioning keyless go fob.

my problem is that i have zero clue as to which components these specifically are. I think that these parts are not “custom” for this particular key version. In the pictures you can see which parts are missing.

Missing parts

Missing parts are on the bottom left. Underneath the button


I have been searching for hours through STAR and WIS but i cannot for the love of god find any circuit board schematic or at least a parts list.

would anyone be able to help or at least have any high quality photos of the components i seem to be missing?

would be appreciated!

cheers!
Remco
the netherlands

 

Here is a photo of my keyfob circuit board circa 2005. This is an earlier version of the DAS3 keyfob; later versions use much more compact components. Two components are missing on your board, "A7s" three-lead component plus a resistor or capacitor. I have no idea what the values are. Perhaps post it on www.reddit.com/r/askelectronics.

I recommend you find an old keyfob via Ebay or similar and take one of two paths:
- remove the two components from the old key fob and install on your circuit board.
- remove the EPROM from your key fob and install on the used key fob. The VIN plus row and track data are coded into the chip. Remove old chip from used key fob and transfer your chip to the used key fob. I have seen posts where this was successfully performed.

Either way, I would pay good money for an experienced technician to perform the work. I'm not bad at board work yet even this is above my skill level.

If it works, let us know.

 

Thanks for the help! Funnily enough a friend of mine saw my post as well and he send me a few pictures of the components in his key. His looks a bit different from yours, but i guess that is due to the difference in continents haha. Either way, i am a bit closer to working this out.

I like your idea of buying a "donor" key for spare parts, so i will look into that. I already followed your advise to post it on reddit (r/AskElectronics) so i expect a few responses on how to tackle the identification process of the SMD in a couple of days.

so again, thanks a bunch!

i will post a few more updates in the following days/weeks of this project for the ones interested

 

Buy a new key fob?