shogun
11-19-2008, 12:03 AM
some info:
.10 Testing Immobilizer (EWS) Systems
EWS stands for the German words “Electronic Wegfahrsperre” meaning electronic driveaway protection. Starting in 1994, BMW vehicles came equipped with EWS, which disables fuel and ignition using door locking input from the General Module to the DME.
There are three versions of EWS currently in use:
• EWS I
• EWS II
• EWS III
4.10.1 EWS I
Beginning with the 1994 model year, all cars were equipped with EWS I. This system still uses a mechanical key but added a “Starter Immobilization Relay” preventing the starter from operating. It functions as a smart relay which only allows starter activation if a specific combination of inputs is met.
The EWS I system is activated when the vehicle is locked from the outside with the key. When activated, the EWS I system performs the following functions:
• Prevents the engagement of the starter
• Disables the fuel injection system
• Controls the neutral safety switch
4.10.2 EWS II
At the start of the 1995 model year, EWS I was replaced with EWS II, which is used on E31, E34, E36, E38 and E39 vehicles. EWS II incorporates all of the functions of the previous EWS I but uses an electronic key. There still is a mechanical key, but an electronic component was added interfacing to the ignition switch which is part of the EWS function. EWS II provides immobilizer protection electronically through a coded chip imbedded in the key and prevents
vehicle operation until the ignition key has transferred the correct code (random changing code) to the EWS control module. EWS II permanently assigns an “Individual Serial Number” or “ISN” to the DME, which is also stored in the EWS. The DME and the EWS modules must match the “ISN” every time the ignition is powered on or the engine will not start.
With EWS I and EWS II, the DME and the EWS are not permanently married or locked together. Diagnostic testing with either a used DME or EWS is possible (EWS II will require ISN re-alignment procedure as outlined below).
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
..... and more
http://www1.snapon.com/display/DocMg...px?fileid=4653
.10 Testing Immobilizer (EWS) Systems
EWS stands for the German words “Electronic Wegfahrsperre” meaning electronic driveaway protection. Starting in 1994, BMW vehicles came equipped with EWS, which disables fuel and ignition using door locking input from the General Module to the DME.
There are three versions of EWS currently in use:
• EWS I
• EWS II
• EWS III
4.10.1 EWS I
Beginning with the 1994 model year, all cars were equipped with EWS I. This system still uses a mechanical key but added a “Starter Immobilization Relay” preventing the starter from operating. It functions as a smart relay which only allows starter activation if a specific combination of inputs is met.
The EWS I system is activated when the vehicle is locked from the outside with the key. When activated, the EWS I system performs the following functions:
• Prevents the engagement of the starter
• Disables the fuel injection system
• Controls the neutral safety switch
4.10.2 EWS II
At the start of the 1995 model year, EWS I was replaced with EWS II, which is used on E31, E34, E36, E38 and E39 vehicles. EWS II incorporates all of the functions of the previous EWS I but uses an electronic key. There still is a mechanical key, but an electronic component was added interfacing to the ignition switch which is part of the EWS function. EWS II provides immobilizer protection electronically through a coded chip imbedded in the key and prevents
vehicle operation until the ignition key has transferred the correct code (random changing code) to the EWS control module. EWS II permanently assigns an “Individual Serial Number” or “ISN” to the DME, which is also stored in the EWS. The DME and the EWS modules must match the “ISN” every time the ignition is powered on or the engine will not start.
With EWS I and EWS II, the DME and the EWS are not permanently married or locked together. Diagnostic testing with either a used DME or EWS is possible (EWS II will require ISN re-alignment procedure as outlined below).
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
..... and more
http://www1.snapon.com/display/DocMg...px?fileid=4653