Mercedes W203 W209 270CDI OM612.962 170HP Engine ECU Kit A6121537779 Key Lock

Mercedes W203 W209 270CDI OM612.962 170HP Engine ECU Kit is a solution designed for vehicles with a diesel engine and an automatic transmission. The set belongs to the Electronic control modules and controllers group, which allows for a consistent, technically correct replacement of key powertrain control system components. It is a practical proposal for workshops and users looking for a matched, factory-original solution when repairing engine electronics.

Specifications and technical data

• SKU: A6121537779-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6121537779
• Substitutable numbers: A6121537779, A 612 153 77 79, 0 281 012 196, 0281012196, A2095452308, A 209 545 23 08
• Fuel type: Diesel
• Gearbox type: Automatic
• Category: ECUs & Computer Modules

Application and function of the ECU kit

The presented engine ECU kit with key and lock is designed for Mercedes C-Class W203 and CLK W209 models with the 270 CDI OM612.962 170HP engine, working in conjunction with an automatic transmission. In practice, this means the ability to restore the complete start authorization path – from the key, through the steering column lock, to the engine controller – based on components originating from a single vehicle.

A kit configured in this way helps reduce diagnostics and programming time, which is particularly important when dealing with vehicle starting issues, CAN network communication errors, or electronic damage caused by power surges or moisture ingress.

Installation and service benefits

Using a complete Mercedes W203 / W209 270 CDI ECU kit with key and lock offers a number of practical service benefits:

• consistency of components originating from a single control system,
• reduced need for advanced coding and adaptation,
• easier diagnostics of faults related to the immobilizer and starting system,
• the ability to restore proper engine control system operation after an electronics failure.

For workshops specializing in the Mercedes brand, this is a convenient solution that helps shorten repair times and reduce the risk of incompatibility between individual modules.

Technical characteristics and compatibility

As an item from the Electronic control modules and controllers group, the kit is designed for use with a diesel engine and an automatic transmission. The appropriate controller software configuration for the 270 CDI OM612.962 unit ensures proper management of injection, turbocharging, automatic transmission operation, and engine protection systems.

Before installation, it is recommended to verify vehicle compatibility regarding engine type, transmission type, and production year, as well as to consult with a diagnostician equipped with appropriate service software. This allows for confirmation that the kit parameters match the configuration of the specific vehicle.

Condition, origin, and practical application

The ECU kit with key and lock is a used item, which in the case of electronics for vehicles such as the Mercedes W203 and W209 is often a rational economic choice while maintaining the factory design and system logic. In practice, it works well both for typical repairs after a controller failure and for more complex work related to wiring harness replacement or control system modernization.

Installation in a specialized service center is recommended to ensure proper connection, any necessary adaptation, and final diagnostics of engine and automatic transmission operating parameters.

If you are planning a comprehensive repair or modernization of the engine area in your Mercedes and need other components from the same group, such as controllers, comfort modules, or engine management units, check out the available parts in the Mercedes electronic control modules and controllers category.

For a broader understanding of how modern electronic systems work in premium cars and how to use dismantled parts for controller repairs, it is worth reading the article on our blog: Driving pleasure for years – how to take care of iDrive systems and electronic modules in BMW 3 and 5 series models.