Quote:
Originally Posted by TwinTurboGTR
...If the battery is dead in the key, the EWS system will not recognize the key and will not start. ...
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Just an FYI to clarify this oft thought misconception...EWS does NOT require the battery in the remote key to work. If it did, then the valet and spare key wouldn't work because they don't contain a battery. EWS is self powered through induction. A 125 KHz RF signal is sent from the EWS control module to the Ring Antenna (around the ignition cylinder) which inductively powers the coil inside the key and allows the transponder soldered to the IC board inside the key to communicate back the ISN.
The battery in the remote key is only used to transmit the 315 MHz (or 433 MHz in Europe) radio frequency from the remote to the aerial in the rear right cargo window to initiate FZV/DWA (central locking/anti-theft alarm siren system).
See the WORKSHOP HINT in the lower right gray box below: