BMW E81 E82 E87 LCI 123d N47S 204HP ECU Kit DDE 7811702 + CAS3 + 2 Keys Manual

BMW E81 E82 E87 LCI 123d N47S 204HP ECU Kit DDE + CAS3 + 2 Keys Manual is a complete electronic set designed for BMW 1 Series models with the 204HP N47S engine, equipped with a manual transmission. The set includes a DDE engine control unit, a CAS3 module, and two keys, providing a cohesive solution for vehicles requiring a full control package replacement. Thanks to the maintained integrity of the components, the set ensures software consistency and comfortable vehicle configuration after installation.

Specifications and technical data

• SKU: 7811702-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7811702
• Substitutable numbers: 13617811702, 7811702, 13618512589, 8512589, 13617812002 13617810002 13617808402 13618506325, 7812002 7810002 7808402 8506325, 13617809002 13617812502 13618508713, 7809002 7812502 8508713, 0281015044, 0 281 015 044
• Gearbox type: Manual
• Category: ECUs & Computer Modules

Purpose and configuration of the ECU kit

The presented ECU kit is dedicated to compact BMW 1 Series models of the E81, E82, and E87 generations after the facelift, in the 123d version with the N47S unit. Combining the DDE controller with the CAS3 module and paired keys creates a coherent security and engine management system, which facilitates restoring full vehicle functionality after an electronics failure or when replacing a damaged controller.

The presence of two keys in the set allows for convenient daily use – one can serve as the main key and the other as a spare. The set is prepared for vehicles with a manual transmission, which is crucial for proper cooperation with the control software and drivetrain logic.

Benefits of using a complete DDE + CAS3 + keys kit

Using a complete engine control unit kit with a CAS3 module and keys limits the need for deep interference with the vehicle's security systems. In practice, this means:

• data consistency between the engine controller and the immobilizer module,
• maintaining compliance with the vehicle configuration regarding the transmission type,
• reduced risk of starting and key authorization issues,
• a more predictable adaptation process in the vehicle.

For workshops specializing in BMW electronics, such a kit provides a convenient base for further configuration, coding, and potential software updates according to the requirements of a specific car.

Application in service practice

The complete ECU kit will work especially well in situations where the engine controller has been damaged, there are problems with the CAS3 module or lost keys, as well as during advanced electronics repairs after flooding or short circuits. The set allows for:

• restoring start and key authorization functions after an electronics failure,
• reducing diagnostic time related to data inconsistency between modules,
• a more organized assembly and configuration procedure compared to replacing individual components.

The used condition means that the components come from an operating vehicle, which in service practice is often a beneficial compromise between cost and functionality, especially in the case of advanced electronic control modules and controllers.

Professional selection and compatibility of BMW electronics

When selecting an ECU kit for a BMW, it is crucial to match it according to the engine version, vehicle generation, and transmission type. A properly selected DDE + CAS3 + keys set minimizes the need for installation modifications and allows you to focus on correct assembly and adaptation procedures. In case of doubts regarding selection, it is worth using identification by OEM number or interchangeable numbers, as well as vehicle data.

To better understand the specifics of used electronics and the principles of safe controller selection, it is worth reading the guide describing the practical aspects of purchasing and installing such components – they are discussed in detail in the article Used automotive electronics on board – why is it worth choosing second-hand ECU modules and sensors?.

Expanding the control system in BMW

If you are planning a comprehensive repair or upgrade of the engine electronics area in your BMW and need other elements from the same group, such as additional controllers, management modules, or related control units, check the available parts in the BMW electronic control modules and controllers category.

Thanks to this, you can build a coherent set of components that will facilitate vehicle servicing, ensure predictable behavior of the drivetrain systems, and allow you to optimize repair costs while maintaining a professional standard of workmanship.