Quote:
Originally Posted by absentmathis
On another note, I've always been skeptical about the recharging. Do we really think these cars have inductive charging in the steering column? I've never seen a charging unit anywhere.
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The Ring Antenna (around the ignition) and the inductive coil (inside the key)...are the "charging unit" that charges the battery inside the key which then powers the
FZV/DWA features of the key. (see
"H" in the previous post which shows the location of the charging coil inside the key...and you can also see the charging coil in pic below)
There's a Ring Antenna around the ignition cylinder...it was initially part of the EWS II system, in the old style keys (starting with BMWs with build dates of 1/1995)...the Ring Antenna was sent a 125 KHz signal from the EWS control module which then thru induction would power up the EWS transponder inside the key. This transponder would then send back the ISN (individual serial number) info to the EWS-CM & DME/ECU...and if the ISNs all matched...the car would be released to start.
With the introduction of EWS 3.2...the Transmitter Receiver's operation was incorporated into the EWS-CM...thus the trans/rev'r was dropped...and when the
new style (diamond shaped) key was introduced. (9/99 build date-up)...the EWS transponder and battery were now soldered to the IC board inside the key...and now the Ring Antenna not only powers up the EWS transponder...
but also powers the rechargeable battery inside the key.
(KL R = ignition position 1)
Your skepticism can be resolved if you ever get a chance to work on the steering column and notice the Ring Antenna (#7 in diagram below) around the ignition cylinder:
Hopefully the info above will help with your skepticism as to if induction is really incorporated into the BMW remote FZV keys. Again, there are THREE feature/systems incorporated into the remote keys. All three systems are independent systems...but do work in conjunction with each other:
- EWS - immobilizing system
- FZV - central locking system
- DWA - anti-theft alarm siren system