Key Fob Doesn't Work Q

[Grady in Texas]

Went out yesterday morning and my key fob didn't work at all (no lock/unlock/doors/trunk) - I only have one key so I can't cross test. The key (manually) locks/unlocks everything electronically - is it reading that from the key chip? I had a low battery message 6 mo (?) ago and replaced the batteries and all was well until yesterday. Before a taking to the dealer (since my indy won't touch key/alarm issues) any suggestions? Thanks Grady.

[Mayorchuck]

Try initializing the key:

http://forums.bimmerforums.com/forum/showthread.php?1913849-HowTo-gt-E38-Key-programming

If that doesn't help I would hit a Radio Shack and replace the batteries again just to be sure.

[xboss]

man, i have replaced the batteries, done the initializing properly, fuel door etc all good and still nothing. Need to check & see if this key is making a signal. The little red light blips when you press the buttons but nothing happens. GL. Let me know what you find out!

[Grady in Texas]

I only got one key with the car and while it looks like up to 9/1999 key, it does NOT have a LED/light (or the hole for it). Does that mean anything? Its getting out the "OK to Start" signal but the initialization didn't work. I'll try changing the batteries again (I got a low battery LED warning a couple of months ago and replaced them.). Thanks Grady

[Qsilver7]

The remote keys are more complicated than what many owners assume. The key operates THREE different systems that are independent of one another but work in conjunction with each other, and may even communicate with the same control modules. A problem with one may or may not affect the funciton of the others...but being familiar with each system can help distinguish where the problem lies:


EWS - immobilizing system...shuts down ignition, fuel, & starter...& does not require the battery/batteries inside the key because it is self powering...using induction (a 125 KHz AM radio signal from the EWS control module or transmitter receiver...is sent to the Ring Antenna, which then sends a signal to the coil inside the key which powers the EWS transponder inside the key...which then sends a data signal back to the other EWS modules)
FZV - remote central locking system, transmits a one-way RF signal (315 MHz or 433 MHz) to a radio receiver in the C pillar which is picked up by an antenna that is embedded in the rear windshield...which then sends a signal to the GM to operate the central locking system
DWA - anti-theft alarm siren system, also transmits a one-way RF signal (same as FZV) but once the data is picked up by the antenna in the rear window and sent to the reciever and then onto the GM...the signal is then finally sent to activate/deactivate the alarm siren system and its various "monitors" around the car (door actuators/trunk/hood/interior motion/tilt sensor/etc)


The battery/batteries inside the key are ONLY USED for the FZV/DWA features...a dead key battery has NO AFFECT on the key's ability to start the car.


The early 3 button remotes (that uses two 1220 batteries) doesn't have the red LED status light. And when you change the batteries...there is no memory...so the key has to be reinitialized.

Around the 1997 model year...BMW changed the design of the remote and the red LED status light appeared and the battery went from two 1220s to one single 2016 battery....as well as a small amount of memory that allows for the changing of the battery without losing programming (see 2nd image below).


http://bimmerboard.com/members/q/original/Old%20Style%20Rubber%20Key%20Battery%20Types%20122 0%202016.jpg

http://bimmerboard.com/members/q/original/Old%20Style%20Remote%20key%202016%20Battery%20Info .jpg
http://bimmerboard.com/members/q/original/Old%20Style%20Key%20Red%20LED%20Status%20Info.jpg

Just to be sure...the instructions for reinitializing the remote keys is posted below. EVERY step must be followed exactly as written or programming could fail. Also make sure that there are no issues with the central locking system or alarm siren system (FZV & DWA)...because an issue with either of these systems could also hinder reprogramming. The failure of the fuel filler door is probably the major issue that affects FZV and reprogramming to fail. And you can tell if there's an issue with the DWA system by the way the red clown nose flashes (red status LED below the rear view mirror...or on top of the dash on e38s):


http://bimmerboard.com/members/q/original/DWA%20Red%20Anti%20theft%20LED%20Status%20Flash.jp g

http://bimmerboard.com/members/q/original/How%20To%20Initialize%20Old%20and%20New%20Style%20 Remote%20Keys.jpg

[Grady in Texas]

Very helpful write-up Thanks for the effort and info. I'm thinking its the battery as I replaced my wife's at the same time and her remote also died. New battery fixed hers. Odd to get 2 different crappy batches of batteries (hers is a 2032 IIRC) or it's part of NKorean's plan to turn us into "Boiled Pumpkins". I'll try again on Monday. Grady

[xboss]

My system refuses to work. Can anybody tell me if INPA will be able to see the key receiver getting a signal from the key? I have to make 100% sure this key is making a signal, looking for a meter but I have a feeling my receiver that is in the c pillar got wet from my leaky sunroof drain.

[Grady in Texas]

New batteries didn't fix it. Afraid is off to the dealer...Argggg.