BMW 3 5 Series E60 LCI E90 M57N2 325d 525d 197HP ECU Kit DME CAS3 Key 7809941

BMW 3 5 Series E60 LCI E90 M57N2 325d 525d 197HP ECU Kit DME CAS3 Key is a complete electronic set from the Electronic control modules and controllers category, designed for BMW diesel systems with the M57N2 engine. The set includes the DME engine control unit, the CAS3 module, and a matched key, which allows for a consistent, professional replacement of the vehicle's control electronics.

Specifications and technical data

• SKU: 7809941-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7809941
• Substitutable numbers: 13617809941, 7809941, 0281015130, 0 281 015 130, 13618509034, 8509034, 13617811151 13617806380 13617806987 13617806152, 7811151 7806380 7806987 7806152, 13618506951 13617805288 13617808314 13617804845, 8506951 7805288 7808314 7804845, 0281014436 0 281 014 436, 61356
• Category: ECUs & Computer Modules

Purpose of the ECU DME CAS3 Key kit

The presented set is dedicated to BMW 3 Series and 5 Series models of the E90 and E60 LCI generations with the M57N2 engine in 325d and 525d versions. Combining the engine control unit with the CAS3 module and the key ensures the consistency of the immobilizer system, which in practice makes it easier to restore full functionality of the powertrain after a failure or during a project upgrade. By keeping the components complete from a single system, the risk of synchronization issues, bus communication errors, and the need for time-consuming adaptation of individual modules is minimized.

Construction and function of the kit components

The ECU kit includes three key components responsible for the operation of the powertrain and start authorization:

• DME engine control unit – manages injection, boost, and protection of the M57N2 unit,
• CAS3 module – responsible for key authorization, immobilizer operation, and start logic,
• key – works with the CAS3 to ensure correct vehicle recognition and engine start. A set configured in this way allows for a technically consistent recreation of the original control system logic, which is particularly important when replacing a damaged controller or during repairs after major electrical faults.

Benefits of using an original BMW module

The original set from the Electronic control modules and controllers category ensures high compatibility with the vehicle's factory installation. This means:

• maintaining the factory operating parameters of the M57N2 engine,
• proper cooperation with other modules in the vehicle's network,
• reducing the risk of software conflicts and diagnostic errors. The complete DME + CAS3 + key set is particularly beneficial for workshops specializing in BMW, as it shortens diagnostic time, simplifies the coding process, and allows focusing on correct installation and vehicle configuration instead of tedious matching of individual modules.

Condition, verification, and practical application

The elements in this set come from the secondary market, which allows for economical repair while maintaining the original manufacturer's specifications. Before installation, it is recommended to perform a standard diagnostic procedure and match the configuration to the specific vehicle, in accordance with BMW service practices. This type of solution is particularly useful in situations where the engine controller has been damaged, there are problems with the immobilizer, or there is a need to replace several related modules at once. The set will prove useful both in professional service centers and in specialized workshops dealing with BMW electronics.

Technical support and additional information

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other components from the same group, such as additional controllers, engine management modules, or diagnostic support systems, check the available parts in the BMW electronic control modules and controllers category. If you are considering using secondary market electronics and want to better understand when choosing a used engine controller or comfort module is justified, check out the guide Second life of electronics – when is it worth choosing used engine controllers, comfort modules, and parking sensors?, where you will find practical tips on selecting and verifying such components.