Electronic Vehicle Immobilization System EWS 2
Electronic Vehicle Immobilization System EWS 2History of BMW vehicle immobilization systems
On vehicles produced up to late 1994 vehicle immobilization can be activated via the antitheft alarm system (DWA) or the on-board computer (BC) fitted on the assembly line.
On vehicles built in the production period from May 1993 to January 1994 this vehicle immobilization can be additionally activated via the central locking system (ZV).
After deactivation via the key and the lock barrel proved to be more and more a weak point in the antitheft system, the newly developed electronic vehicle immobilization (EWS 1) has been fitted as standard since January 1994 in all BMW vehicles (exception: E30, E32, E36 without ZV). This is documented by SA900. This vehicle immobilization system fulfilled the requirements of fully comprehensive insurance providers at that time
The development of vehicle immobilization systems made further progress resulting in all BMW vehicles worldwide being fitted as standard with an electronically coded vehicle immobilization system (EWS 2) as from January 1995. The EWS 2 prevents the vehicle from being driven under its own engine power as the result of tampering with the ignition lock or doors.
The electronic vehicle immobilization system, stage 2 (EWS 2) fulfilled the more stringent requirements of the European fully comprehensive insurance providers that came into force in January 1995.
Insurance requirements
The vehicle must be equipped with an electronic vehicle immobilization system that operates independent of the mechanical lock system and which prevents vehicle operation by means of coded intervention in the engine management.
This immobilization system must be self-arming and must be effective on leaving the vehicle or on locking it at the latest.
Deactivation must not take place with the mechanical key but rather it must be implemented by electronic means.
Explanation of important terms
Term
Explanation
Transponder
Hybrid term derived from the words transmitter and responder. The transponder is a special transceiver.
Transponder chip
Electronic module in the key which basically consists of the transceiver, a small antenna coil and a memory.
ISN
Individuelle S teuerger�tenummer (= individual control module number), i.e. a number (production number) allocated individually by the control module manufacturer to each engine control module (DME/DDE).
System overview
The EWS 2 system consists of the following components:
Key with transponder
Loop antenna (coil) at steering lock
Transceiver electronics (S/E module)
EWS control module
Engine control module (DME/DDE) with coded start enable input
Key with transponder
The transponder is a special transceiver in the key which can communicate with the EWS control module via the transceiver electronics (S/E module). The transponder chip integrated in the key consists of the transceiver, a small antenna coil and a read/write memory.
The transponder chip is powered by the transceiver module via the loop antenna at the steering lock. This means that no battery is necessary in the key for power supply. The power supply and data transfer take place in the same way as a transformer between the loop antenna (coil) at the ignition lock and the antenna coil integrated in the key. The maximum range for writing and reading is 2 cm.
The transponder memory contains:
Key data
Service data
Important
Each individual key (with or without remote control) contains a transponder chip with its own key data thus making it unique!
Loop antenna (coil) at steering lock
The coil consists of 75 windings and fitted on the lock barrel of the ignition lock.
Transceiver electronics (S/E module)
The electronic transceiver module (S/E module) serves the purpose of data processing and controlling data transfer to the transponder and also communicates with the EWS control module. This communication takes place on a serial bi-directional single-wire line.
The transceiver module is installed in the vicinity of the steering column. It receives power as from ignition lock position 1.
EWS control module
The EWS control module is the interface to the electronic transceiver module (S/E module), engine control module and starter.
The main tasks of the EWS control module are:
Acquiring the key data from the transponder.
Coded enabling of the engine management with a valid key.
Storing the individual control module number (ISN) of the respective engine control module for coded data exchange.
Managing the key data for a total of 10 keys.
Power is supplied via terminal 30.
Engine control module (DME/DDE) with coded start enable input
The engine control module (DME/DDE) was designed such that the ignition (terminal 15) and the fuel supply are enabled only when a correct enable signal is received from the EWS control module.
The basis of this enable signal is the individual control module number (ISN) of the engine control module.
The engine control module (DME/DDE) must identify this enable signal before it then enables the ignition signal (terminal 15) and the fuel supply.
For this reason, after replacing the engine control module (DME/DDE), the individual control module number (ISN) of the new engine control module must be transferred by means of coding (DIS tester or MoDiC) into the EWS control module. The individual serial number is not available from the outside.
Key identification and start procedure
Ignition lock in position 2 The transponder is powered via the loop antenna and sends the key data to the EWS control module.
The EWS control module then checks the key data to ensure it is correct and only then sends an enable signal to the engine management system and starter.
On automatic transmission vehicles, the position of the gear selector lever is additionally determined and the starter is enabled only in position P or N.
After the engine has started, the EWS control module generates new key data and transfers them to the transponder.
The starter is switched off when the EWS control module detects a certain engine speed for a certain period of time. This engine speed variant depends on the type of engine.
CAUTION!
For safety reasons, the EWS control module features a code-dependent run-on time (typically 10 s). The run-on time begins as soon as the ignition lock is in position 0 and no diagnosis telegrams are sent to the EWS control module.
Observe the following points when checking keys:
The EWS control module does not acquire any key data from the key during the run-on period. For this reason the engine can be started with any mechanically fitting key (also with an electronic defect) during the run-on time when changing a key!
To check keys, proceed as described in the following:
If the service tester DIS or MoDiC is connected: Unplug diagnostic connector from vehicle.
Switch ignition lock to position 0 and remove the key used for this purpose.
Wait for run-on time to elapse, ignition lock must remain in position 0!
Insert the key to be checked, turn ignition lock to position 2.
Attempt to start the engine.
The duration of the run-on time can be read out with the diagnostic program of the EWS control module as the "self-arming time" under "service functions", "read coding data".
Note
For safety reasons, during a start enable, the central locking is opened from a secured status.
Typical procedure
It is necessary to initialize and synchronize the control modules and transponder during vehicle production or after replacing individual EWS components. The typical procedure at the production plant as well as at the dealer is described in the following:
First-time initialization at the production plant
The EWS control module and the 4 vehicle keys are initialized with the key data created in a programming station. The key data for a further 6 replacement keys that have not yet been cut are additionally written in the EWS control module. All key data (of a total of 10 keys) are stored in a database. The individual control module number (ISN) is then read out of the engine control module and entered in the EWS control module. Initialization is now concluded and the vehicle is ready for operation.
Procuring replacement keys
Replacement keys can be obtained from a sales point only via a BMW dealer where one of the 6 replacement keys fitting the vehicle is programed This key is not a copy of the lost key, but rather a new key.
Important
The sales center always makes a new key! A total of not more than 6 replacement keys suitable for the installed EWS control module can be made and handed over! The key data of delivered replacement keys are deleted from the database!
The order for making a key in the sales center cannot be further processed before all the necessary customer and dealer data have been submitted in full.
CAUTION!
Every request for a key is documented so that all inquiries from insurance companies and authorities can be followed up.
In view of the more stringent antitheft requirements, the procurement of replacement keys will in future be more involved than it has been in the past.
As from key No. 5 (first replacement key) all replacement keys will feature an 'E' on the key bit for identification purposes.
Disabling keys
With the aid of the DIS tester, a lost key can be disabled on the vehicle and re-enabled if the key is found again. All keys still in the customer's possession must be submitted for this purpose.
Replacement of the EWS control module
A pre-initialized control module must be obtained from the designated sales center for the purpose of replacing the EWS control module. The procedure is similar to that for procuring replacement keys.
The new EWS control module must then be encoded in the vehicle. During this procedure the individual control module number (ISN) of the engine control module (DME/DDE) is transferred to the EWS control module. The encoding procedure must be carried out as follows:
Select the defective EWS control module that is still installed in the vehicle with the coding program. The data are then buffered in the MoDiC or DIS tester.
Install new EWS control module.
Encode new EWS control module, i.e. transfer the buffered data.
If diagnosis is no longer possible on the defective EWS control module, it will be necessary to enter the vehicle identification number and the central encoding code by hand in the new EWS control module.
Replacement of engine control module (DME/DDE)
After replacement, the new engine control module must be encoded by means of the DIS tester or MoDiC. During this procedure the individual control module number (ISN) stored in the engine control module (DME/DDE) is transferred to the EWS control module.
Replacement of the transceiver module (S/E module)
Initialization is not necessary.
Obtaining spare parts
In addition to the production plants, the following sales centers are currently equipped with programming stations for the purpose of initializing EWS components:
For Europe: Dingolfing (Central Parts Distribution Depot)
2 centers in the USA for North, Central, South America and Canada
For East Asia, Australia and Oceania: Japan
For Southern Africa: South Africa
The following EWS 2 components are available as spare parts through the sales centers:
Pre-initialized transponder key
Pre-initialized EWS 2 control module
Pre-encoded/non-coded DME/DDE
Steering lock barrel
Lock barrel for doors and lids/flaps
Lock barrel with key without transponder
Pre-initialized uniform lock system with EWS 2 control module
Transceiver electronics (S/E module)
Loop antenna (coil)
Procedure for loss of all 10 keys
By providing all the necessary data, the authorized customer is able to obtain from the sales center a new EWS control module and new initialized transponder keys with the previous mechanical key code via a BMW dealer.
If all 10 keys and all acquired data (also in the database center) are lost it will be necessary to replace both the EWS control module as well as all the keys. Since, in this case, the parts are not standard stock, the parts are supplied only by the Central Parts Distribution Depot (ZKA).
Diagnosis
The diagnosis capabilities of the EWS system are supported by the use of the 'electronic vehicle immobilization EWS' diagnostic program (available on DIS tester).
Troubleshooting is greatly facilitated by the selection of fault symptoms and working through corresponding test modules.
In addition, functions are provided for the purpose of determining the validity of existing keys ('key test') and checking correct data matching between the DME/DDE and EWS control module ('EWS DME/DDE data comparison').
Proceed as follows in the case of complaint:
Connect DIS tester to diagnosis socket in the vehicle.
Switch ignition lock to position 2.
Select model series
Model series E31/34/36:
On page 'Diagnosis CONTROL UNITS' select the EWS control module under '16 ELECTRONIC VEHICLE IMMOBILIZATION EWS'.
Schematic circuit diagrams are available in paper document form.
Model series E38:
Identify vehicle. The page 'Diagnosis vehicle identification' follows
Press 'function selection' button. Select 'EWS system' n the 'Diagnosis function and component selection' page for the drive or body.
Continue in the diagnosis program by pressing the 'test plan' button.
The corresponding functional description, schematic circuit diagrams, pin assignments and installation locations of the EWS components are provided under 'Documents'.
Encoding
Encoding is of decisive importance in the EWS system. After replacing the EWS control module or the engine control module (DME/DDE) the EWS control module must always be correctly adapted by means of encoding otherwise it will not be possible to start the engine.
Procedure:
Connect DIS tester or MoDiC.
Switch ignition lock to position 2.
If replacing EWS control module:
Select 'Replacement coding'.
Select the EWS control module under 'control module selection'.
The encoding procedure begins with reading out the data from the old, defective EWS control module still fitted in the vehicle.
The data entered in the defective EWS control module are buffered in the DIS tester or MoDiC. After replacement the buffered data are entered in the newly installed EWS control module.
Important
This procedure (read data from defective component - install new part - transfer data to new part) must always be carried out in this order when replacing an EWS control module!
If the EWS control module to be replaced no longer has communication capabilities it will be necessary to enter the vehicle identification number and the central encoding code (ZCS) by hand. All other service data can no longer be read out of the old EWS control module and are therefore lost.
If replacing engine control module (DME/DDE):
The encoding procedure is carried out after replacing the engine control module.
Select programming
Select the engine control module under 'control module selection'.
Calibration with the EWS control module takes place automatically during the programming procedure.