4100187 BMW E39 EWS 3 Immobiliser Control Module – OEM Used & Tested

Description

This BMW EWS 3 immobilizer control module is a genuine OEM anti-theft component for the BMW E39. Primary OEM number 4100187. It is designed to read the transponder in the ignition key, test the key code against its stored data and pass the start release to the engine control unit, so that the E39 starts only with a correctly coded original key. It works together with the ignition lock and the engine management of the same car.

Its job is to recognize the key, exchange a rolling security code with the engine control unit and enable the starter and fuel injection only when the code is accepted. A properly working EWS 3 module supports dependable starting, strong theft protection and correct operation of the immobilizer system across the key, the ignition lock and the engine management.

Common signs of a faulty unit include a no start with a flashing security light, keys that are not detected, random starting failures, an engine that cuts out soon after starting and diagnostic faults about the key or engine control communication. When the module fails, the immobilizer may keep the engine disabled, so the car stays parked until a matching working module is fitted and set up.

This is a used original part, removed from a vehicle and tested before sale. Match the exact OEM number 4100187 before ordering. Professional installation is recommended, and EWS alignment with the engine control unit, key programming or coding is normally needed where applicable, since the module is tied to the vehicle it was removed from.