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Old 10-04-2021, 10:38 AM
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Qsilver7 Qsilver7 is offline
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Location: Indiana, USA
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Looks like the "experiment" cleared up some misconceptions.

The central locking system(FZV) and anti-theft alarm siren system (DWA) is controlled by the GM/GM III. The manual locking procedure for the driver's door (when using the door lock cylinder under power) is carried out over the P-bus by way of the door module to the GM/GMII. When using the remote fob...the 315MHz RF (radio frequency) signal is sent from the remote fob, to the FZV aerial in the rear (left) cargo window...then onto the FZV amp/receiver...then onto the GM/GM III where the signal is then sent to lock/unlock and arm/disarm the vehicle over the P-bus.

As already mentioned...starting the car is carried out by EWS...which is a separate system that uses a 125 KHz AM signal...where the remote fob, Ring Antenna, EWS control module, and ECU/DME are all communicating with each other and verifying that an encrypted ISN (individual serial number) matches.

Below is some BMW tech info that shows the location of some of the components and explains the mechanical disconnection that occurs when the vehicle is "double-locked" versus "single-locked".

{location of FZV antenna for BMW Tourings & SAVs}

{E53 X5 FZV amp/receiver location}

{BMW CCA Member #191509 - (for more info see:}
  • 2013 f06 650ix GC (1/13 build date) Black Sapphire exterior/Schwarz (black) Nappa Leather interior
  • 2014 f15 X5 50i (11/13 build date) Space Gray exterior/Mocha Nappa Leather interior
  • 2006 e53 X5 4.4 Sterling Gray
  • 1997 e38 740iL (sold) Arctic Silver
  • 1999 e39 540iT (sold) Orient Blue
  • 1995 e34 525iT (sold) Alpine White
  • 1991 e32 735iL (sold) Schwarz (black)
  • 1985 e30 325e (sold) Bronzit
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