2004 BMW Z8 remote control

9
EWS
System Components
Key with Transponder
Four keys are initially supplied with each vehicle.
Each key contains a wireless electronic chip
(transponder chip). The function of the transpon-
der is to receive and transmit data to the EWS II
control module. The transponder contains a
wireless read/write EEPROM in addition to a
small capacitor and coil for self power capabili-
ties.
The functions of the EEPROM are:
• Store codes for key identification, password and changing codes.
• Receive and respond to coded messages from the EWS II control module.
Power for the transponder is produced through the inductive coil and stored in the capac-
itor. Each time the key is inserted into the ignition AC voltage in the antenna ring induces
voltage in the inductive coil.
All keys either with remote or without, includ-
ing wallet and valet keys contain transponders.
8510108
8510107
Key Notes:
Keys have temperature oper-
ating range of -40
0to 800C.
Keys are shock resistant from
a height of 10 meters.
Inductive coil
Capacitor
Read/Write
EEPROM

20
EWS
EWS III (3.3)
EWS III (3.3) is installed in the 1998 E38 from 5/97 production, in the 1998 E39 from 9/97
production, in the E46beginning of production, in the E52and E53 beginning of pro-
duction.
Purpose of the System
The purpose of the EWS III (3.3) system is to add greater theft protection by providing a
higher level of sophistication than previous systems. The new “Rolling Code” provides an
additional theft deterrent through a changing of the ISN everytime the vehicle enters the
start sequence.
Components changed in the EWS III (3.3) system include:
• EWS III (3.3) Control Module.
• DME Control Module.
• Transmission Range Selection Input.
System Components
EWS III (3.3) Control Module
The EWS III (3.3) Control Module uses the same 13 pin connector as EWS III (3.2) but func-
tions differently. The EWS III (3.3) module has a “Rolling Code” ISN assigned to it during
manufacture. The “Rolling Code” is burned into
the module and cannot be overwritten by ZCS
Coding or DME alignment procedures.
The “Rolling Code” is a one way signal from the
EWS III (3.3) control module to the DME and is
similar in operation to the data exchange
between the EWS control module and the key
transponder.
The “Rolling Code” will be different each time the
start operation is begun. The “Codes” are taken
from the “Rolling Code Table” which is assigned
at the factory to the EWS III (3.3) control module
and the DME.
8510133
Workshop Hint:
While it is possible to initialize a key to another
vehicle to check for remote operation, use cau-
tion. All keys for Bothvehicles must be avail-
able. The initializing process, causes loss of
operation of keys previously initialized.
All keys must be initialized at the same time.