Mercedes W221 OM642.930 235HP Engine Control ECU Kit A6421507391 Automatic

Visual condition of the part

The product shows signs of use visible in the photos. Mercedes W221 OM642.930 235HP Engine Control ECU Kit Automatic is a specialized module from the Electronic control modules and ECUs category, designed to work with the 235 HP OM642.930 diesel unit in the W221 generation S-Class model. The ECU is configured to operate with an automatic transmission, ensuring precise management of engine parameters and seamless integration with the drivetrain.

Specifications and technical data

• SKU: A6421507391-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6421507391
• Substitutable numbers: A6421507391, A 642 150 73 91, A0024460640, A 002 446 06 40, 0281013522, 0 281 013 522
• Gearbox type: Automatic
• Part type: Engine Control Unit (ECU)
• Category: ECUs & Computer Modules

Purpose and function of the engine control unit

The presented ECU is responsible for the advanced control of the OM642.930 unit in the Mercedes S-Class W221, including fuel injection, boost control, starting strategy, and communication with the vehicle's onboard systems. Using a dedicated module for the automatic transmission version allows for maintaining consistency between gear shift logic and engine torque characteristics, which translates into stable and predictable drivetrain performance. The ECU belongs to the Electronic control modules and ECUs group, making it an integral part of the vehicle's electronic architecture that communicates with other modules via the data bus. Proper matching to the specific engine and transmission version minimizes the risk of communication errors and software compatibility issues.

Compatibility, replacement numbers, and identification

The component was designed for the 235 HP OM642.930 unit in the W221 body, meaning its control map and hardware configuration are tailored to the specific requirements of this engine version. The ECU has an assigned OEM part number and associated interchangeable numbers, which facilitates clear identification and selection of the correct module during repair or replacement. Before purchasing, it is recommended to verify compatibility by part number and vehicle equipment to ensure proper operation with the existing electrical installation and software. As a result, the ECU can be used both as a replacement part in case of failure of the existing module and as a base for potential adaptation at a specialized service center.

Benefits of using an original ECU

Using an original ECU dedicated to the OM642.930 in the W221 allows for maintaining factory engine performance, including refinement, dynamics, and fuel consumption consistent with the manufacturer's specifications. The module is adapted to work with an automatic transmission, supporting the correct operation of functions such as kick-down, driving style adaptation, and smooth gear shifting. Compared to universal solutions, the original ECU provides better integration with safety and comfort systems, such as traction control, electronic stability programs, and advanced diagnostic functions. For workshops and users, this means a more predictable installation process and easier service maintenance.

Condition, origin, and practical application

The offered module is a used part, which makes it an attractive cost-effective solution while maintaining the original manufacturer's specifications. Such ECUs are frequently used by professional automotive electronics repair services, especially in the event of a factory ECU failure or communication issues within the vehicle network. Before installation, it is recommended to perform standard service procedures, such as diagnostics, potential software matching, and adaptation to the specific vehicle. This allows the ECU to fully take over the functions of the previous module, restoring proper engine operation and cooperation with the automatic transmission.

More solutions for Mercedes electronics

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 control modules, auxiliary controllers, or drivetrain controllers, check out the available parts in the Mercedes electronic control modules and ECUs category. For users interested in the broader context of electronics and ECU repairs in premium vehicles, a guide describing the use of salvaged parts in control system maintenance may be helpful – more information can be found in the article Driving pleasure for years – how to take care of iDrive systems and electronic modules in BMW 3 and 5 series models using salvaged parts?. Additionally, practical tips on safely choosing used components online, including electronic modules, are provided in the guide Safe purchase of used car parts online – a step-by-step guide, which can facilitate making informed purchasing decisions.