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Old 12-10-2012, 03:01 AM
tastytoast tastytoast is offline
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Location: Bay Area, CA
Join Date: Nov 2012
Posts: 2
Mein Auto: 2001 540i
bringing this thread back from the dead...

I'm having the same issue on my 01 540i. I have one key that works perfectly, and another that intermittently works. sometimes it works like a charm, sometimes it takes 10 times to get the doors to un/lock.

So, I came across this thread and the OP mentioned the contacts were the source of the problem, not the battery. So I decided to try a few things and wanted to share the results.

First of all, the base line situation. The key would rarely work, I would say absolutely guaranteed the key worked <30% of the time. Accurately it probably worked around 15-20%. Very sporadically it would work. (sometimes it would work the first time I pushed it, sometimes it wouldn't work at all)

Two things I tried:
1. I threw the key into a tupperware and ran hot water over it for ~10-15 minutes. It got nice and toasty inside the tupperware (the air expanded quite a bit), the key was a strong warm. Not too hot though. After I warmed it up I massaged it for about 5 minutes, massaging the buttons and what not. Tested the key with the car, no improvement.

2. Kind of frustrated, I slapped the key on my leg. The key has been off the keyring for all of these situations. So what I did was I gripped the key by the metal portion and slammed the fob portion into my right leg, one-two inches up from my knee, to the inside 2-3 inches. Did that about 5-10 times. Noticeable improvement with the key button functions. So this gave me an idea, I went to a hard table, I lined it with 2 towels, and I proceed to "scientifically" smack the crap out of the key fob on the table. I rotated the angle of impact, on the sides, smacking the buttons, the back, the tip, didn't smack the metal part though, because that might snap the metal key portion off the fob. Tried not to over do it, just solid smacks against a cushioned hard surface. I went out to test the key. The immediate results are that guaranteed >80% of the inputs are working now. To be more accurate it's about 90% of the time. A little more detail about how hard I smacked the key, I wasn't too afraid of it breaking, considering I would have replaced the key with a new keyshell like described by the OP.

These results are just the first night of testing. I just wanted to jot down this idea so that maybe somebody could take it a step further and say that contacts are largely the source of this problem. My logic for the time being is that jolting the key like this loosens up any debris that may have accumulated in the contacts, or loosens the "hardness" factor the OP mentioned about his/her keyset. If the key function reverts back to a crappy status, I'll be back to post results. If I don't respond then it's still working

Last edited by tastytoast; 12-10-2012 at 03:16 AM.
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