Mercedes W169 A150 M266.920 95HP Engine Control Unit ECU A2661531491 Automatic

Mercedes W169 A150 M266.920 95HP Engine Control Unit ECU Automatic is a specialized module from the Electronic control modules and controllers group, designed for precise management of the powertrain in the A-Class W169 model. This used controller ensures factory engine control logic while maintaining a favorable cost-to-functionality ratio and the possibility of professional diagnostics and adaptation.

Specifications and technical data

• SKU: A2661531491
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2661531491
• Substitutable numbers: A2661531491, A 266 153 14 91, A0034466040, A 003 446 60 40, 5WK90990
• Gearbox type: Automatic
• Category: ECUs & Computer Modules

Purpose and function of the engine controller

The engine control unit (ECU) in the Mercedes A150 is responsible for coordinating key powertrain operating parameters, such as fuel injection, ignition, and interaction with security systems. As an original component for the Mercedes brand, the module is designed for seamless integration with the factory electrical installation and other vehicle systems.

The ECU from this series is structurally prepared for integration with vehicles equipped with an automatic transmission, which is crucial when selecting the appropriate controller in terms of software and communication with the transmission module.

Benefits of using an original ECU module

Using an original engine controller in the A-Class W169 allows for maintaining vehicle configuration consistency and reducing the risk of compatibility issues. In practice, this means:

• proper cooperation with the factory immobilizer and electrical installation,
• stable communication via the data bus with other modules,
• possibility of full diagnostics using professional service testers,
• easier adaptation and coding compared to universal replacements.

A used module with preserved OEM structure is a good solution for repairs where both technical correctness and service cost control are important.

Vehicle fitment and selection by part numbers

When selecting an engine controller for the Mercedes W169 A150, it is crucial to compare the OEM part number and interchangeable numbers with the vehicle data (in particular, information derived from the VIN). Only the compliance of these parameters guarantees correct cooperation with the existing wiring harness, engine accessories, and automatic transmission.

In practice, it is recommended to verify the following before purchase:

• compatibility of the engine version and transmission type,
• type of controller software used,
• information about any interchangeable reference numbers.

This approach minimizes the risk of needing additional programming beyond standard adaptation procedures.

Condition, service application, and installation

The offered controller comes from the used parts segment, which allows for economical repair of the engine control system while maintaining the original electronic architecture. The module is primarily intended for service applications: replacing a damaged ECU, resolving communication issues in the vehicle network, or restoring proper powertrain operation after an electronics failure.

During installation, standard procedures for Mercedes engine controllers must be followed, including potential coding, immobilizer adaptation, and synchronization with the automatic transmission. It is recommended to perform these tasks in a workshop equipped with appropriate diagnostic software.

More about used electronics and related components

If you want to better understand how to safely choose used control modules and sensors, what to look for when selecting by VIN and OEM numbers, and what the installation and coding process looks like, check out our guide: Used automotive electronics – ECU modules and second-hand sensors.

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 other ECU units, check out the available parts in the Mercedes electronic control modules and controllers category.