Mercedes W164 ML320 OM642.940 Diesel Engine Unit ECU Kit A6421509478 + Keys

Mercedes W164 ML320 OM642.940 Diesel Engine Unit ECU Kit is a solution designed for vehicles with the OM642.940 unit and an automatic transmission. The kit includes the electronic engine control module along with matched immobilizer components (keys), which facilitates restoring the proper operation of the powertrain after a failure or engine replacement. Thanks to maintaining compatibility with the factory Mercedes electronics architecture, installation and adaptation in the vehicle are significantly simplified.

Specifications and technical data

• SKU: A6421509478-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6421509478
• Substitutable numbers: A6421509478, A 642 150 94 78, 0 281 013 757, 0281013757, A1645451308, A 164 545 13 08
• Fuel type: Diesel
• Gearbox type: Automatic
• ECU type: Engine Control Unit
• Category: ECUs & Computer Modules

Purpose and function of the ECU kit

The presented kit belongs to the Electronic control modules and ECUs group and acts as the central management unit for the diesel engine. The Engine Control Unit is responsible for precise fuel dosing, boost pressure control, fuel injection system operation, and cooperation with the automatic transmission, traction system, and safety systems.

The presence of matched keys in the kit allows for maintaining consistency with the vehicle's factory security system, which is particularly important when replacing the ECU in modern Mercedes models, where the immobilizer is closely linked to the engine electronics.

Benefits of using an original Mercedes module

Using an original Mercedes control module ensures:

• preservation of factory diesel engine control maps,
• proper cooperation with the automatic transmission and onboard systems,
• consistency with the vehicle's electrical installation and communication bus,
• possibility of diagnostics using standard service tools.

For workshops and users, this means stable engine operation, predictable vehicle behavior, and easier resolution of potential operational issues.

Application in the OM642.940 engine with automatic transmission

OM642.940 diesel engines in the Mercedes W164 ML320 require an ECU designed specifically for this powertrain configuration. The presented ECU kit is prepared to work with the diesel engine and automatic transmission, which is crucial for the proper functioning of features such as gear shifting under load, torque control, or the operation of driver assistance systems.

Thanks to this kit, it is possible to replace a damaged ECU or perform a complete engine electronics conversion without the need for deep interference with the vehicle's factory security features.

Condition, verification, and practical application

The item comes from dismantling and is intended for users and service centers looking for a proven solution for repairing the engine control system in a Mercedes W164 ML320. Choosing a used ECU kit with keys allows for reducing repair costs while maintaining high compatibility with the original vehicle configuration.

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 auxiliary control units, check the available parts in the Mercedes electronic control modules and ECUs category.

More about the operation of electronic modules

For a better understanding of the operating principles of modern engine controllers and other electronic modules, it is worth familiarizing yourself with practical tips regarding diagnostics and repairs. In the context of working with used controllers, an article describing the handling of iDrive systems and controllers in premium vehicles may be helpful – you can find it here: how to take care of electronic modules and engine controllers using parts from dismantling.