Drive Away Protection System (EWS)

Model: EWS I/EWS II/EWS III/EWS III D E31/E34/E36/E38/E39/E46/E52/E53, Production Date: All since 1/94

Objectives
After completion of this module you should be able to:
• Explain the differences in the EWS systems.
• List the components that make up the different EWS systems.
• Describe the operation of each system.
• Understand and relate the data exchange sequence between the EWS and DME.

Drive Away Protection
The first version of Drive Away Protection was installed on production vehicles 9/93 through 12/93.
Purpose of The System
The purpose of the Drive Away Protection system was to reduce vehicle theft as mandated by the European Insurance Commission to combat the high theft rate in European Countries.
This first version of the Drive Away Protection System added a circuit from the General Module to the DME. The added circuit was spliced into the existing code function from the Board Computer (BC) to the DME.
The components of the Drive Away Protection System are:
• Door Lock Switch
• General Module
• Board Computer
• DME
System Components
Door Lock Switch
The door lock switch provides a 12V (High) signal to the GM when the vehicle is locked from the outside. The switch also provides a Low signal to the GM when the vehicle is unlocked.
General Module
The GM receives the lock and unlock signals from the door lock switch and signals the DME with a 12V High signal when the vehicle is double locked or with a Low signal when this vehicle is unlocked.
Board Computer
The Board Computer (BC) through its’ code function provides a High signal to the DME to disallow vehicle operation or a Low signal to allow vehicle operation.
DME
The DME looks for a High/Low signal from the BC or GM and dependent on the signal, it will either allow or prevent vehicle operation.

Principle of Operation
When the vehicle is locked from the outside, a High signal is sent to the GM from the door lock switch. The GM receives this High signal and outputs a High signal to the DME. The circuit from the GM is spliced into an existing circuit from the BC to the DME. A High signal from the GM (or BC) causes the DME to cancel the fuel and spark functions to the engine resulting in a no-start condition. The vehicle must be unlocked with the key or the code function of the BC cancelled for the DME to allow engine operation.

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 features. At the time of introduction the system was referred to as Electronic Drive Away Protection which in German is Electronische Wegfahrsperre or 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 • DME

Door Lock Cylinders and Switch
The door lock cylinders and switch input a High/Low signal into the GM informing the GM of lock status. The signal is High when the system is in Double Lock.
General Module
The GM receives the High/Low signal from the door lock switch and outputs a High/Low signal to the Starter Immobilization Relay. A High signal indicates the vehicle is in Double Lock.
Board Computer
The Board Computer outputs a High/Low signal to the Starter Immobilization Relay. A High signal indicates the Code function is active.
Transmission Range Switch
The Transmission Range Switch input with automatic transmission equipped vehicles allows the Starter Immobilization Relay to provide a Neutral safety switch function. A High signal from the Trans range switch indicates the transmission is in Park or Neutral. A Low signal indicates the transmission is in a drive gear and will prevent starter operation.
DME
The DME is both an input device (after 6/94) and an output device of the Starter Immobilization Relay.
Input
Starting with production 6/94, the DME “TD” (engine speed) signal was added to the inputs of the Starter Immobilization Relay. This additional input allows the relay to provide a starter protection feature. The internal relay contact (starter operation) opens if the TD signal exceeds 60 Hz which equals the following engine speeds:

• 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 maximum 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 signal 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 condition 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.

EWS II

Starting with 1/95 production, 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 introduce 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

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 transponder 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 capabilities.

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 capacitor. Each time the key is inserted into the ignition AC voltage in the antenna ring induces voltage in the inductive coil.

Ring Antenna

The Ring Antenna is an inductive coil installed around the lock cylinder which provides power for the transponder in the key and the communication link (antenna) between the key and the transmit/receive module.

Transmitter/Receiver Module

The Transmitter/Receiver module supplies power to the transponder through the ring antenna and controls the flow of data between the transponder and the EWS II control module.

Data transmission between the transmitter/receiver module and the transponder takes place over a radio frequency of 125 KHz amplitude modulated AM signal. The transmitter/receiver module converts the analog data received through the AM signal to digital data and transfers it to the EWS II control module over a single wire bi-directional data interface.

Workshop Hint: On E34 and E36 models the transmitter/receiver module is located under the dash near the steering column. On E 31, E38 and E39 models the transmitter/receiver module is located in the steering column cover on the right hand side of the column.

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 vehicle 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.

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 continue.

• 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.

Principle of Operation

The starting sequence involves communication between all the components of the system. Any break-down in the communication process will result in a no start condition. The sequence of events for vehicle starting is as follows:

• The key is inserted into the lock cylinder and switched “ON”. The transmitter/receiver module is powered through KL R. The transmitter/receiver module sends a 125kHz. AM signal to the ring antenna. The AM signal induces voltage in the key coil and powers up the transponder.

• Powered up, the key transponder sends the key identification code to the transmitter/receiver module via the 125kHz AM signal (1). The transmitter/receiver module converts the AM signal to a digital signal and sends it to the EWS II control module (2).

• The EWS II control module verifies the key identification code and checks to see if the key is enabled (3).

• Upon accepting the key as valid and enabled the EWS II control module sends a digital password (4) to the transmitter/receiver module, which converts the data to an AM signal (5) and sends it to the transponder via the ring antenna (6).

• 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.

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 contain 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 control 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 identified 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 signal when the clutch is depressed.

complete file for download with drawings and additional info http://www.unofficialbmw.com/images/BMW_EWS.pdf