Electronic Immobilization (Ews) - BMW 1999-2005 M3 Service Manual

Central Locking and Anti-Theft
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Electronic
Immobilization (EWS)
E46 cars are equipped with a passive
theft-prevention system. The Electronic
Immobilization System (EWS 3.3)
makes it impossible to start the engine
using any means other than the special
keys furnished with the vehicle.
Note:
EWS is sometimes also referred to
as Driveaway Protection.
If a vehicle key is lost or stolen,
the electronic authorization for that
key can be cancelled using the
BMW scan and diagnostic tools
DIS or MoDiC.
Force applied to a key can
damage the electronic circuitry. A
damaged key will not start the
engine.
In the EWS system, the ignition key is
embedded with a computer chip and
permanently coded. The key
communicates with the vehicle using a
transponder in the key and a ring
antenna surrounding the steering lock
cylinder.
A primary code is programmed into the
key and into the vehicle itself. A
secondary code is changed every time
the vehicle is started. If the key code
and EWS control module code do not
match, the engine management control
module and the starter are disabled.
EWS ignition keys cannot be
duplicated.
The system is designed to have up to
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