Key fob programming frustrations.

Carpe ZM

New member
 PA
Yes, I’ve searched through the existing threads… Here’s my dilemma. I bought my 2003 Z4 less than a year ago. It came with two keys. One worked with the remote to lock, unlock and open the trunk and start the car, etc. The other one would work with the physical key to unlock the doors and start the car, but the remote buttons did not work. On the working remote, the range was very very short, so I figured the battery was getting weak. When I say short, I had to be within a foot of the car for it to lock or unlock or open the trunk. I ordered two of the correct replacement batteries on Amazon, and started with the nonworking remote. The battery that was in the remote was at 2.7 V, the replacement battery was at 3 V. I soldered the new one in place, absolutely no difference and try to operate the lock, unlock or trunk buttons. So I figured there must be something else wrong with that key. I opened up the working key. That one was reading 3.2 V on the battery before I touched it, so I did NOT replace that battery. Now, however, the previously working remote only works to lock the doors, and will not unlock or open the trunk! I have tried the reprogramming method 25 times or so, and cannot get either key to program to the car. Help?
 
With the key that's lost unlock and trunk, I'd say it's the switches themselves. If it had lost programming none of them would work.

It's possible the remote part of the other key has just died. For a friend with an E46 (same key) I did once swap the immobiliser chip from a dead remote key and put it into a second hand key that was then successfully programmed to the car so that could be something to try if you're good at surface mount soldering.
 
I don't think it's the switches, my key fob worked fine until I split it open in preparation to change the battery. I was very very careful, I'm 99.9% sure that I didn't nick anything inside with the razor blade!
 
I was thinking more that, at 20 years old, it might not take much to upset them (dry joints just hanging on etc.)
 
What was the dealer quoting me $320
US for a new key fob programmed to my car, I had to at least give it a shot.
 
Get an aftermarket key with transponder and an AK90 programmer (to program the transponder to the EWS). You will have to have someone cut the key blank but still way cheaper than a factory key. I've got two aftermarket keys, and they've worked great for the last 5 years.
 
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