Mercedes W251 R 350 CDI 642.950 224HP Engine Unit ECU Kit A6421508100 Key Lock

Mercedes W251 R 350 CDI 642.950 224HP Engine Unit ECU Kit is a specialized electronic control module designed for precise management of the diesel powertrain in the automatic transmission version. This component from the Electronic control modules and controllers category is responsible for coordinating key engine operating parameters, ensuring stable performance, predictable throttle response, and proper integration with vehicle systems. Thanks to its factory design, the ECU maintains compatibility with the car's electrical architecture and enables professional repair of the powertrain.

Specifications and technical data

• SKU: A6421508100-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6421508100
• Substitutable numbers: A6421508100, A 642 150 81 00, 0281015939, 0 281 015 939, A1649050100, A 164 905 01 00
• Fuel type: Diesel
• Gearbox type: Automatic
• ECU type: Engine Control Unit
• Category: ECUs & Computer Modules

Purpose and function of the engine controller

The presented engine controller is dedicated to the diesel unit in the Mercedes R-Class W251 series, specifically the R350 CDI model with 224 HP and engine code 642.950. As an Engine Control Unit, it is responsible for processing sensor signals, controlling fuel injection, air metering, and coordinating with the automatic transmission system. A correctly selected ECU is crucial for maintaining factory engine performance, smooth operation, and the proper functioning of safety systems.

Compatibility and replacement numbers

The controller belongs to the group of original solutions used in Mercedes vehicles and is associated with a specific OEM part number and a set of interchangeable numbers. The presence of multiple reference numbers facilitates the selection of the appropriate module for a specific vehicle configuration, which is particularly important when repairing engine electronics in modern diesel units. Before purchasing, it is recommended to compare the markings with the damaged controller or service documentation to ensure full hardware and software compatibility.

Technical characteristics and application

As an item from the Electronic control modules and controllers category, this ECU is designed for operation in a diesel fuel system and for integration with an automatic transmission. It is responsible for:

• managing the combustion process in the diesel engine,
• coordinating operation with the automatic transmission,
• handling safety features and emergency modes of the powertrain,
• communicating with other vehicle modules via the data bus.

This type of controller is essential for the professional replacement of a damaged ECU, restoring proper engine operation and full functionality of the powertrain.

Product condition and benefits of choosing a used ECU

The offered engine controller is in used condition, which allows for an economical vehicle repair while maintaining the manufacturer's original specifications. Choosing a verified used ECU is often a sensible solution in the event of engine electronics failure, especially in vehicles with complex electronic architecture. This allows for reduced service costs while maintaining compatibility with the vehicle's factory systems.

To better understand when it is worth opting for a used engine controller and how to approach the purchase of automotive electronics consciously, it is worth reading our guide: The second life of electronics – when is it worth choosing used engine controllers, comfort modules, and parking sensors?

Support with selection and repair expansion

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

For more serious powertrain failures, when you are also considering replacing the complete engine, a practical step-by-step guide may be helpful: How to buy a used car engine and avoid a bad deal – a step-by-step guide. This will help you plan the scope of work and select the right components for your vehicle.