Z3 remote door locks

one of my first posts here regarded the intermittent problem of doors not remotely locking/unlocking on my 2002 3.0i Z3 (stock locking system w/o alarm on 2001-02 models). the occasional problem only happens outdoors (not in garages), on warmer days and on a warm car that has recently moved (any distance that causes just the right vibration or jarring). car battery is charged (though it show no voltage drop when the problem is there vs. 0.1 V drop when functioning correctly) and the problem affects both keys equally. when the problem occurs, it can sometimes be remedied by holding the key up close to the interior rear view mirror (where the receiver is).

my dealer has just replaced the mirror and i still have the problem. while i'll be going back to pursue the next attempt to fix this, i'm very interested in compiling a list of all who have experience this problem (and particularly those folks who have gotten it fixed) i'm already corresponding with several others and i do believe that this is more than an isolated issue. however, like lots of new car problems, some folks let it slide.

if you have experienced this door lock problem, please take the time to respond with details. i'll keep all respondents updated on fixes relayed to me.

Hi Dr Z,
I couldn't believe my eyes when I read your posting. I'm having the exact same problem and my 2002 2.5 Z3 is currently in service for the 4th time for this issue. Last time they replaced the module in the rear view mirror with no effect. It's good to know that I'm not the only one experiencing this annoying malfunction. Of course the dealership has never seen nor heard of this issue before, and it seems like I'm the one doing all of the troubleshooting. It would really help my case if I knew how many other Z3 owners have this problem and of course if there is a fix.

Interesting to read this now.
I have the same problem appearing now on my 3.0 Z3 2001. It has been gradually getting worse over the years and I thought it was a battery issue in the keys. Both keys have the same problem.

So now who did ever find out what was wrong.

H

I have only had my car 2003 Z4 for one summer and have it put away for the winter so cannot coment on if it happens in the cold. However last summer during a couple of hot days (30 deg C) it took me several tries to get the car doors unlocked.

I was going to get my G5 model reprogrammed but spent too much money replacing some other more important parts.

Are these the keys with the built in door unlock buttons?

If so, they have a battery or capacitor inside them that is charged inductively when the key is in the ignition.

It sounds like they are discharging and then you have a very low signal. Like a low battery in the FOB style remotes.

Regular keys with close open buttons of rubbery type. In garage it always works outside I have to most of the time place key in front of windshield and mirror.
So is problem in key or receiver in mirror. Is there an antenna or what?

I noticed the same problem with my car a few days ago, outside on a sunny day. I thought maybe it was the battery, but I'm pretty sure I had just replaced it in that key. Always works in the garage though.

My 2001 2.5 has the same intermittent symptoms. When it happens I place key in trunk lock and turn. Works every time. Miller 1000