BMW E81 E82 E87 LCI E88 N47S 123d ECU Kit DDE 7811702 + CAS3 + Key Manual

BMW E87 N47S 123d Engine Computer ECU 7811702 is an original electronic control unit designed for the N47S engine in the 123d model, intended for use with a manual transmission. This factory-original controller from the Electronic Control Modules and Controllers category ensures proper engine operation management, injection parameters, and vehicle protection systems.

Specifications and technical data

• SKU: 7811702-2
• 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, 61359147220, 9147220
• Gearbox type: Manual
• Category: ECUs & Computer Modules

Purpose and Function of the Engine Controller

The presented engine computer is dedicated to the BMW 1 Series E87 powertrain with the N47S engine in the 123d version. The controller is responsible for precise fuel injection control, boost pressure management, accessory operation, and coordination between the engine and the manual gearbox. This allows for maintaining stable operating parameters, correct throttle response, and compliance with factory control maps.

As a component within the electronic control modules and controllers group, the ECU integrates signals from sensors, monitors the operation of sub-assemblies, and communicates with other vehicle systems via the data bus. A correctly selected controller is crucial when replacing a damaged module, restoring full powertrain functionality without the need for mechanical engine intervention.

Selection by OEM Number and Interchangeable Numbers

This engine computer has an assigned OEM part number and a set of interchangeable numbers, which facilitates matching it to a specific vehicle configuration. When selecting a controller, it is advisable to pay attention to:

• The compatibility of the OEM number with the currently installed module,
• Compatibility with the list of interchangeable reference numbers,
• The link to the specific N47S engine version and vehicle equipment.

This approach minimizes the risk of communication problems within the vehicle network, diagnostic errors, and incorrect engine operation after installation. If in doubt, it is recommended to use the VIN and service documentation to confirm the module's full compatibility.

Condition, Installation, and Technical Aspects

The offered controller is a used part, sourced from disassembly, which allows for economical vehicle repair while maintaining the original manufacturer's specifications. The module is designed to work with a manual transmission, so it is particularly important to match it to the correct gearbox type – using a controller from a different configuration (e.g., from an automatic version) may result in improper system operation.

Before installation, consider the programming or adaptation procedures required for the specific BMW model, including potential coding, immobilizer synchronization, and communication checks with other modules. Correct installation and configuration will restore full engine control system functionality without the need for costly replacement with a new part.

Benefits of Choosing a Used BMW ECU

Using an original, used engine computer for the BMW E87 123d with the N47S engine is a solution that combines controlled costs with the preservation of factory control logic. The main advantages of this choice include:

• Maintaining the original electronic architecture of the vehicle,
• The ability to match by OEM number and interchangeable numbers,
• Consistency with factory engine maps and equipment configuration,
• No need to use unverified universal solutions.

If you are looking for other parts in the BMW Electronic Control Modules and Controllers category, check out the BMW Electronic Control Modules and Controllers available in our assortment to find a complete solution for your car.

Technical Support and Knowledge of Used Electronics

When choosing a used ECU, understanding hardware and software compatibility, as well as proper installation principles, is crucial. A detailed discussion of these issues, along with practical examples of selection by VIN and OEM numbers, can be found in our guide: Used Automotive Electronics Onboard – Why Choose Second-Hand ECUs and Sensors?. Reading this article will help you better plan the controller replacement and avoid common mistakes when working with BMW electronics.