1994 BMW 5 SERIES ignition

5
EWS
EWS I
EWS I was installed on vehicles beginning production 1/94, replacing the original Drive
Away Protection System.
Purpose of the System
The next level of compliancy with the European Insurance Commission required additional
changes from the previous system. An additional component was added called the Starter
Immobilization Relay. This relay module provides added theft prevention and safety fea-
tures.
At the time of introduction the system was referred to as Electronic Drive Away
Protectionwhich in German is E
lectronische Wegfahrsperreor EWS.
The EWS I system consisted of the following components:
• Starter Immobilization Relay
• Door Lock Cylinders and Switch
• General Module
• Board Computer (if equipped)
• Transmission Range Switch
• DME Engine Speed Signal (Beginning 6/94 Production)
• DWA (E31)
System Components
Starter Immobilization Relay
The Starter Immobilization Relay was installed on E31, E34 and E36 vehicles.
It was in the following location:
E36 -In the relay carrier to the left of the steering column.
E31/E34-In the “A” pillar above the footwell kick panel speaker.
The Starter Immobilization Relay functions as a “Smart Relay”, a relay which receives inputs
from various sources looking at the proper combination of input signals before activating a
component, in this case the starter.
The Starter Immobilization Relay receives input from:
• Ignition Switch • General Module • Board Computer
• Trans Range Switch • DME (>6/94)
And processes output to:
• Starter • DME8510104

7
EWS
• 4 cylinder =1800 RPM
• 6 or 12 cylinder =1200 RPM
• 8 cylinder =900 RPM
The relay contacts will close when the exceeded Hz value drops to 5Hz below the maxi-
mum value. This is intended as a safety feature to prevent starter motor activation when the
engine is running above these speeds.
Output
The DME receives a High/Low signal from the Starter Immobilization Relay. When the sig-
nal is High, the DME does not activate injector or ignition operation.
DWA (E31)
The DWA outputs a High/Low signal to the Starter Immobilization Relay indicating the con-
dition of the alarm system. A High signal indicates the alarm is armed, preventing vehicle
starting.
Principle of Operation
The EWS Starter Immobilization Relay receives it’s inputs from the Ignition switch, GM (or
DWA), BC, Trans Range Switch and the DME (after 6/94). The relay will prevent engine
starting if:
• The vehicle is locked from the outside. The GM receives the High signal from the
door lock switch and sends a High signal to the EWS.
• The BC Code function is set.
• A DWA High signal is received. (E31only)
• A Low signal is received from the Trans Range Switch.
• The engine speed signal from the DME exceeds 60Hz. (after 6/94)
The Ignition and injection functions of the DME are disabled and the KL50 start signal to
the starter is opened to prevent starter operation.
Workshop Hints:
Starter Immobilization Relays are different for manual and automatic vehicles, check to ensure correct
relay is installed.
The Starter Immobilization Relay is not on the Diagnostic Link. Conventional troubleshooting techniques
using the DISplus, a DVOM and the correct ETM are necessary.
Loss of input from the GM or BC will allow the engine to start.
Loss of input from the Trans Range Switch will NOTallow the engine to start.

8
EWS
EWS II
Starting with 1/95production, all vehicles were equipped with a new EWS system, EWS II.
This change was once again brought about to meet the next level of compliancy with the
European Insurance Commission regulations.
Purpose of The System
Changes to the European Insurance Commission regulations made it necessary to intro-
duce a new theft protection system with greater capabilities and a higher level of security.
The EWS II system operates independent of the mechanical key. The mechanical key only
makes a request of the vehicle starting system. Verification of the key electronically is
required before the starting procedure is initiated.
The system features wireless communication between a programmed EEPROM housed in
the ignition key and the EWS II control module. A key which is properly coded to the EWS
II control module is required before starting operation continues. The EWS II and the DME
control modules are synchronized through an Individual Serial Number (ISN).
The ISN, stored in the EWS II,
must match that of the DME every
time the ignition is switched “ON”
before engine operation is
allowed.
EWS II was installed on E31, E34,
E36, E38 and E39 vehicles.
Major components of the EWS II
system are:
• Key with Transponder
• Ring Antenna
• Transmitter/Receiver Module
• EWS II Control Module
• DME Control Module
8510111
EWS II

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

11
EWS
EWS II Control Module
The EWS II Control Module is linked to the BC, GM, DME, Trans Range switch and the
starter for drive away protection operation. The module incorporates an integral starter relay
and stores data and codes for communication with the transponder chip.
The function of the EWS II module is to provide improved drive away protection for the vehi-
cle and it incorporates many features of previous systems:
• Lock out of the starter when the code function of the BC is set.
• Disable injection and ignition through the DME.
• Prevent starter engagement with engine running.
• Recognition of Park/Neutral position with automatic transmission.
New features that have been added:
• Disable injection, ignition and starter operation until a correct key is recognized.
• EWS and DME synchronization through the use of the ISN.
• Release of double lock when a correctly coded key is switched on.
The EWS II control module stores the following data
for the key transponder inter-link:
• Key identification code- up to 10 keys.
• Key password.
• Changing code- up to 10 keys.
Workshop Hint:
On E31, E36, E38 and E39 models the
EWS II control module is located behind
the glove box in the electrical carrier.
On E34 models the module is located on
the drivers side of the vehicle behind the
knee bolster.
8510106
Typical component locations
E36 shown

12
EWS
DME
The DME is redesigned to incorporate the new ISN code. As of production 1/95 all DME
control modules will contain the unique ISN number and will not interchange with previous
DME’s. The following new features are added to the DME:
• Unique ISN assigned to DME during manufacture, it can not be changed, altered or
overwritten.
• The BC code input to the DME is eliminated.
• The DME and EWS II control module must be synchronized. The DME sends the ISN to
the EWS II module which stores the number for replay to the DME.
• The ISN received from the EWS II module during start-up is compared to the internal
ISN of the DME. The numbers must match before the start operation is allowed to con-
tinue.
• The ISN is sent to the DME continuously by the EWS II module with the key on.
• The DME will ignore loss of the ISN after the engine is running.
• The DME retains the ISN information from the EWS II module for 10 seconds after the
ignition is switched off.
Restarting or switching the ignition on within the 10 seconds cancels the key
identification process.
Workshop Hints:
The DME is located in the E-Box.
Remember the EWS-DME link stays active for 10
seconds while testing keys for proper operation.
65101108

14
EWS
• If the transponder accepts the password as correct the transponder releases the
changing code (7) to the transmitter/receiver module which converts this AM signal to
digital (8) and sends it to the EWS II module (9).
• If the changing code received by the EWS II module is correct, the status of the BC,
transmission range switch and TD is examined. With correct input status the internal
starter relay is energized and the starter motor begins to operate (10). At the same
time the EWS II module sends the ISN to the DME via the single wire communication
link (11).
• If the ISN code stored in the EWS II module matches that of the DME, the drive away
protection is cancelled and injection and ignition is enabled.
• During the process of sending the ISN to the DME, the EWS II module sends a new
changing code to the transponder through the transmitter/receiver and ring antenna.
The transponder stores the changing code until
the next starting sequence.
8510122
8510124
10
11
Workshop Hints:
The entire process takes place in under 750ms.
If the starter operates, the key has been recognized as
OK and the key requires no further diagnosis. Check
status of ISN in DISplus or MoDic.
Recognition of a valid key by the EWS II module caus-
es it to send an unlock signal to the GM if the vehicle is
in double lock.
Transponder
Chip in KeyTransmitter
Receiver
Module
EWS II
EWS II

15
EWS
Replacement Procedures
Keys
Up to 6 additional keys may be ordered as replacement keys. The EWS II control module
is codeable for only 10 keys (4 delivered with vehicle and 6 replacement).
EWS II Control Module
Replacement EWS II Control Modules must be ordered VIN specific. EWS II modules con-
tain the VIN and coding from the factory to recognize the key codes. Modules from other
vehicles will not recognize keys as being valid and not start the engine.
EWS II Control Modules store the Central Coding Key (ZCS) and the VIN. If the EWS II con-
trol module is replaced the system must be ZCS coded (SIB 61 02 96 and TRI 61 01 95).
The EWS II module must be synchronized with the DME (aligned). There is no limit to the
number of times the ISN may be changed in the EWS II module.
DME Control Module
The DME Control Module is not ordered VIN specific and must be programmed during
replacement. The ISN from the new DME must
be transferred to the EWS II module using the
DISplus or MoDic.
Key Activation
Keys that are lost or stolen may be deactivated
or made to not operate the starter functions.
The SERVICE FUNCTIONS of the DISplus or
MoDic for EWS II contains a “Bar/Release
Code” function that activates and deactivates
keys of the EWS II. Any key may be “Barred”
except the key in the ignition at the time of
deactivation. The lost or stolen key can be iden-
tified by the identification of the remaining keys.
There is no limit to the number of times a key
can be activated/deactivated.
EWS II Update
Beginning MY 1997 E31 and E36 vehicles with manual transmissions were updated to include a clutch
pedal position switch. The clutch switch signal is provided by a hall-effect sensor providing a high sig-
nal when the clutch is depressed.
Note: A “Barred” key will not start the engine, it
will still unlockthe vehicle.