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Sigma alarm fob issue - battery?

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Evening folks, my sigma alarm fob battery appears to have finally given up. (1993 E34 520i) Anyone know what’s required to replace the battery ie is it a simple replacement or is it a solder in job. Couldn’t really find much on line about them. The only number on it is MPT 1340, but when you google that it comes up with just about every sigma alarm fob ever made! Any guidance appreciated before I hack it to bits and make an ar5e of it, i’ve heard some of these fobs can be prone to losing ‘memory’ if you don’t complete the battery swap quickly. Thanks!

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Hi,

 

Not sure that Sigma the car alarm brand are still around - a very quick search finds me this - https://www.in-car-advancements.co.uk/sigma-car-alarms.html

 

Perhaps ask them? 

 

I'd imagine its a small watch type battery anyway, so should be easily replaceable. 

 

Worst case scenario is if it does break / go faulty etc, you'd replace it all with a new modern alarm if the fob/electronics can't be repaired/re-coded etc.

 

Cheers, Dennis

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I think you can use AC38 and AC111 fobs

 

I had a programmer see here and was able to add new fobs - the 38 & 111 have a screw off back to change battery.

 

I would think a decent car security shop would still be able to help.

 

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Tad late to this party unfortunately. I have reason to believe my E34 had this type of alarm. AFAIK, to replace the battery, you had to peel off the cover. Apparently back in the day dealerships could supply a new cover/sticker. It's a basic button cell battery, and not a solder affair, but I don't know if memory is lost or not swapping them out. Some info is available on Subaru forums as they used the exact same alarms.

See here also:

 

Keliuss

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