Mercedes W204 C220 CDI 170HP 646.811 Engine Unit ECU A6461502734 Automatic

Mercedes W204 C220 CDI 170HP 646.811 Engine Unit ECU Automatic is a specialized electronic control module designed for diesel units paired with an automatic transmission. This used controller from the Electronic control modules and ECUs category allows for the restoration of proper powertrain operation without the need to invest in a new component. It is a solution for users expecting proven electronics with factory performance characteristics.

Specifications and technical data

• SKU: A6461502734-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6461502734
• Substitutable numbers: A6461502734, A 646 150 27 34, A0054467440, A 005 446 74 40
• Fuel type: Diesel
• Gearbox type: Automatic
• Category: ECUs & Computer Modules

Purpose and function of the engine controller

The presented engine computer is responsible for the comprehensive management of the diesel unit's operation, including fuel dosing, boost pressure control, idle speed control, and cooperation with the automatic transmission. Thanks to precise control algorithms, the ECU coordinates the operation of injectors, sensors, and actuators, which translates into stable power, correct throttle response, and predictable drivetrain behavior under various load conditions.

A properly selected controller for a specific engine version and transmission type is crucial for maintaining factory acceleration parameters, fuel consumption, and engine operating culture. The ECU engine computer in this model has been designed to work with the high-pressure diesel system and the automatic transmission system, which minimizes the risk of communication errors between modules.

Benefits of using a pre-owned ECU

Choosing a used engine controller is a solution that allows for a significant reduction in repair costs while maintaining the vehicle's original electronic architecture. This type of module, once properly matched and adapted, enables:

• restoration of proper starting and stable operation of the diesel unit,
• elimination of errors related to ECU communication with the automatic transmission,
• maintenance of factory injection maps and torque characteristics,
• cost reduction compared to purchasing a new controller.

For workshops and individual users, this means the ability to react quickly to engine electronics failures while maintaining high consistency of operating parameters. The used control module is particularly attractive for older vehicle models, where the availability of new components may be limited or economically unjustified.

Integration with the diesel system and automatic transmission

This engine computer has been developed to work with a diesel fuel system, which means it supports specific injection strategies, fuel pressure control, and turbocharger operation. At the same time, the controller communicates with the automatic transmission, transmitting information about load, torque, and rotational speed, which allows for smooth and predictable gear shifts.

A correctly selected ECU for a given drivetrain variant reduces the risk of limp mode, jerking during gear changes, or uneven idling. For workshops specializing in the Mercedes brand, this is a component that enables a comprehensive powertrain repair while maintaining the consistency of all electronic modules.

Professional selection and installation

To fully utilize the potential of this controller, installation in a specialized workshop equipped with appropriate diagnostic software for ECU adaptation, immobilizer coding, and verification of communication with other modules is recommended. Proper configuration ensures:

• stable engine operation across the entire rev range,
• proper cooperation with safety and comfort systems,
• no errors in the controller's memory after the adaptation is completed.

Thanks to this, the electronic control module can be used as an effective repair solution without the need for mechanical intervention in the powertrain unit.

Related products and technical knowledge

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 controllers, engine management modules, or parameter control systems, check the available parts in the Mercedes electronic control modules and ECUs category.

Before deciding to install a used controller, it is worth reading practical tips on selecting and verifying vehicle electronics – the article "A second life for electronics – when is it worth choosing used engine controllers, comfort modules, and parking sensors?" will be helpful, where you will find specific advice regarding ECUs and other electronic modules.