Electronic Immobilization System (EWS)
"All BMW vehicles, 1995 models and newer, utilize an Electronic Immobilization System called the EWS II. The EWS II system uses an antenna ring around the ignition cylinder to energize a small transponder chip hidden in the key. When the ignition is turned on, this chip is energized and the antenna ring sends the code to the EWS II control unit. If the code is correct the vehicle will start and continue to run. If an invalid code is sent, the EWS II control unit will "tell" the engine control module to shut down and the vehicle will not start..."
For the purpose of DOHC swaps, you may use even EWS DMEs provided you use an aftermarket chip that disables EWS.
These DMEs do not have EWS:
- Early Silver Label DMEs
- All Red Label 413 DMEs
Later silver label DMEs past 12/94 do have EWS and will require a chip to function.