MERCEDES C W203 Alarm Motion Sensor is a component from the Electronic Control Modules and Controllers category, designed for the factory security system in C-Class W203 generation models. It enables precise detection of motion in the rear of the vehicle, supporting the efficient operation of the alarm and enhancing the car's protection level.
Specifications and technical data
- SKU: A2038219751
- Mark: Mercedes (Genuine OE)
- Condition: Used
- OEM Part Number: A2038219751
- Substitutable numbers: A2038219751, A 203 821 97 51, EM
- Location on the vehicle: Rear
- Color: Grey
- Category: ECUs & Computer Modules
Purpose and Function in the Alarm System
The alarm motion sensor is responsible for monitoring the space in the rear cabin or trunk area, depending on the vehicle's configuration. Upon detecting unauthorized movement, it transmits a signal to the alarm control unit, allowing for a rapid response from the security system. This ensures that the Mercedes C W203 alarm system maintains full functionality and provides the driver with a higher level of parking security.
As an element of the original electronic architecture, the sensor works in conjunction with factory controllers and wiring harnesses, which minimizes the risk of communication errors and diagnostic issues.
Mounting Parameters and Vehicle Integration
The presented sensor is designed for installation in the rear of the vehicle, in accordance with the factory alarm system design. This placement ensures:
- effective coverage of the monitored area inside the car,
- proper cooperation with other alarm components,
- stable mounting in original mounting points.
The grey housing allows for an aesthetically pleasing integration of the component into the interior trim or trunk lining, without compromising the vehicle's styling. By adhering to the factory installation concept, the mounting process is orderly and predictable for service technicians.
Benefits of Using an Original Electronic Module
Choosing an original motion sensor for the Mercedes C W203 from the Electronic Control Modules and Controllers category offers primarily:
- compatibility with the electrical system – matched connectors and operating parameters facilitate installation and reduce the need for modifications,
- proper cooperation with the factory alarm – maintaining the system's logic of operation, including responses to breaches of the protected zone,
- easier computer diagnostics – the module is recognized by service systems designed for this Mercedes generation.
The product comes from the segment of used electronic components, which allows for optimizing the cost of repairing or restoring the alarm's functionality while maintaining the original system design.
Condition, Verification, and Selection by Numbers
The sensor is offered as a used component, which in practice means it comes from a dismantled vehicle and has been verified for its suitability for further use. This type of solution is often chosen for alarm system servicing, where compatibility with factory electronics is crucial, rather than the visual "newness" of the part.
To select the appropriate sensor for a specific version of the Mercedes C W203, it is advisable to use the OEM part number or interchangeable numbers – this allows for confirming compatibility with the given equipment configuration and car year. If in doubt, verification by VIN number in the service documentation or parts catalog is recommended.
If you want to better understand how to safely use used modules and sensors, you will find practical tips in the guide: used car electronics – second-hand ECU modules and sensors.
Expanding the Security System in a Mercedes
When expanding or undertaking comprehensive repairs of the alarm system, it is also worth considering other Mercedes Electronic Control Modules and Controllers. If you are looking for similar components for this model, check the available Mercedes Electronic Control Modules and Controllers to assemble a complete set of components that comply with the factory specifications.
