Mercedes-Benz S W221 S350 CDI BlueTec OM642 Engine Control Unit ECU A6421508900

Mercedes-Benz S W221 S350 CDI BlueTec OM642 Engine Control Unit ECU is a factory electronic engine control module designed for the OM642 engine in the S-Class W221 S350 CDI BlueTec model. This item from the electronic control modules and controllers category ensures the proper operation of the injection system, exhaust gas control, and engine operating strategies in modern Mercedes diesels.

Specifications and technical data

• SKU: A6421508900
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6421508900
• Substitutable numbers: A6421508900, A 642 150 89 00, 0281016656, 0 281 016 656, KZ
• Category: ECUs & Computer Modules

Purpose and Function of the OM642 Engine Controller

The presented ECU controller is responsible for the comprehensive management of the OM642 diesel engine in the Mercedes S-Class W221 S350 CDI BlueTec. It controls, among other things, fuel injection quantity, boost pressure, exhaust gas recirculation system operation, and interaction with the vehicle's onboard systems. This allows the powertrain to maintain stable operating parameters, appropriate dynamics, and compliance with exhaust emission standards.

The module is part of the original Mercedes electronic architecture, which translates to proper communication with the vehicle's wiring, CAN network, and other controllers. It is a key component for correct starting, idle operation, operation under load, and for service diagnostics.

Benefits of Using an Original Mercedes ECU Module

Using an original engine controller in the Mercedes S W221 S350 CDI BlueTec offers a number of practical benefits:

• Full integration with vehicle electronics – the module works with factory safety and comfort systems, minimizing the risk of communication errors.
• Stable engine operating parameters – proper control maps and regulation algorithms help maintain the smoothness and performance of the OM642 unit.
• Diagnostics with factory tools possible – support by standard service testers facilitates configuration, adaptations, and potential software updates.
• Operational safety – a correctly selected controller reduces the risk of incorrect fuel delivery or turbocharger overboosting.

Module Characteristics and Condition

The offered controller belongs to the group of electronic control modules and controllers used in modern Mercedes powertrains. It is a used part, sourced from disassembly, which significantly reduces repair costs compared to purchasing a new component, while maintaining factory hardware specifications.

Before installation in a specific vehicle instance, it is recommended to verify compatibility by OEM number and interchangeable part numbers, as well as to consult with an electrician or diagnostician regarding potential programming, immobilizer coding, or adaptation to the specific car. Proper matching of hardware and software parameters is crucial for the system's trouble-free operation.

Selection, Installation, and Service Aspects

To correctly select this controller for the Mercedes S W221 S350 CDI BlueTec, it is advisable to rely on:

• vehicle identification by VIN number,
• comparison of OEM part number and reference numbers,
• checking the OM642 engine version and car year.

The installation itself should be performed by a workshop experienced in automotive electronics. In many cases, it is necessary to carry out adaptation procedures, coding, or cloning data from the original controller to preserve security functions and individual vehicle settings.

For users considering the purchase of used ECU controllers and other onboard electronics, the Global Parts guide will be useful – Used automotive electronics onboard – why choose second-hand ECU modules and sensors?. The article discusses selection by VIN/OEM, compatibility issues, and practical installation tips.

Other Mercedes Electronic Control Modules and Controllers

If you are also looking for other Mercedes electronic control modules and controllers for your car, check out our dedicated offer: Mercedes electronic control modules and controllers. This will allow you to easily assemble the remaining electronic system components in one place, maintaining component consistency and ease of selection for a specific model.