Mercedes R171 W204 C209 W220 Ignition Key Remote Control Unit Fob A2117663506

Used key – requires programming

The key requires programming (coding) by a specialist to be fully functional. Mercedes R171 W204 C209 W220 Ignition Key Remote Control Unit Fob is an original component from the Electronic control modules and controllers group, designed for remote control and ignition authorization. The product is offered in for parts or not working condition, making it an excellent donor for components, housings, or connectors for specialized repairs in Mercedes vehicles.

Specifications and technical data

• SKU: A2117663506
• Mark: Mercedes (Genuine OE)
• Condition: For parts or not working
• OEM Part Number: A2117663506
• Substitutable numbers: A2117663506, A 211 766 35 06, A 212 766 40 06, A2127664006, A 212 766 70 06, A2127667006, A 204 905 08 04, A2049050804
• Category: ECUs & Computer Modules

Module purpose and function

The presented Mercedes R171 W204 C209 W220 Ignition Key Remote Control Unit Fob is designed to work with the electronic authorization system in Mercedes vehicles, where the key acts as a remote control transmitter and an identifier in the starting system. This element belongs to the Electronic control modules and controllers group, responsible for communication between the key, the immobilizer, and other control units in the vehicle. Thanks to its original origin, the module retains the factory design of the circuit board, connectors, and housing, which is essential for precise electronics repairs, reconstruction of damaged remote controls, or restoring installations in vehicles after collisions or water damage.

Application in service and automotive electronics

Due to its for parts or not working condition, the module is intended primarily for electronics workshops, services specializing in the Mercedes brand, and advanced hobbyists. It can be used for, among other things:

• sourcing functional SMD elements and components from the printed circuit board,
• transplanting housings, buttons, or connectors in damaged remote controls,
• comparative analysis when diagnosing faults in comfort and starting systems,
• training exercises in soldering and automotive electronics repair. The original design of the module facilitates matching to specific equipment versions and the vehicle's electrical configuration, which is important for professional repairs.

Compatibility and replacement numbers

The Mercedes R171 W204 C209 W220 Ignition Key Remote Control Unit Fob is linked to a dedicated OEM part number and has assigned interchangeable numbers, which facilitates the selection of the correct element based on service documentation or manufacturer catalogs. In practice, this means it can be used as a reference base when comparing electronics, identifying hardware versions, and verifying compatibility with other modules used in Mercedes vehicles. Before purchasing, it is recommended to verify compatibility by part number and vehicle configuration so that the module can be effectively used as a donor for components or training material.

Technical condition and installation recommendations

The offered element is classified as for parts or not working, which means it is not intended for direct installation as a fully functional module. Treat it as a source of parts, housings, or material for advanced electronics repairs. Any attempts to restore full functionality require appropriate diagnostic equipment, experience in working with automotive electronics, and access to specialized service software. It is recommended that work on immobilizer, comfort, and starting systems be performed by specialized workshops due to the connection of these systems to vehicle safety and the necessity of maintaining correct synchronization with other controllers.

Expert support and electronics selection

If you want to better understand how to effectively use used electronic modules, how to select them by OEM number, and how to assess hardware and software compatibility, check out our guide: Used automotive electronics on board – why is it worth choosing second-hand ECU modules and sensors?. This is a practical source of knowledge for workshops and those involved in automotive electronics. If you are planning a comprehensive repair or upgrade of the control electronics area in your Mercedes and need other elements from the same group, such as comfort controllers, body modules, or engine control units, check the available parts in the Mercedes electronic control modules and controllers category. For workshops that want to reduce vehicle downtime and optimize costs, the following article may also be helpful: Availability of car parts off the shelf vs. repair time – how do used OEM parts shorten workshop stays?, which describes the practical benefits of using readily available OEM elements.