Mercedes W221 Wheel ABS Speed Sensor Rear Right O/S A2215400117

Mercedes W221 ABS Sensor Rear Right Rear Right is an original component of the braking system, responsible for precise reading of the wheel's rotational speed on the rear right axle. Thanks to its factory fit for the W221 platform, it ensures stable cooperation with the ABS system and traction control, which translates to safe braking and predictable vehicle behavior. This is a solution for users looking for a proven part with parameters matching factory equipment.

Specifications and technical data

• SKU: A2215400117
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2215400117
• Substitutable numbers: A2215400117, A 221 540 01 17
• Location on the vehicle: Rear, Right
• Category: ABS Speed Sensors

Purpose and Function of the ABS Speed Sensor

The ABS speed sensor in this model is responsible for the current measurement of the wheel's rotational speed on the rear right side of the vehicle. The signal from the sensor is analyzed by the braking system controller, which, based on this, regulates the pressure in the brake circuits, preventing wheel lock-up during sudden braking. A correctly functioning sensor affects:

• the effectiveness of the ABS system in emergency situations,
• driving stability during braking on slippery surfaces,
• cooperation with assistance systems (e.g., traction control, stability control – if present in the specific vehicle configuration).

Fit for Mercedes W221 and Vehicle Placement

The presented sensor has been designed specifically for the Mercedes W221 platform, which means structural compatibility with the factory braking system. Its placement on the vehicle is the rear right side, so this component is intended for installation only at this specific point of the body. Such a fit minimizes the risk of installation problems and eliminates the need for modifications to the wiring.

By maintaining the original geometry and correct positioning relative to the pulse ring, the sensor ensures a stable signal reading, which is important for the operation of active safety systems.

Characteristics of a Used Part

The offered sensor is a used part, sourced from dismantling. This type of part allows for economical repair of the ABS system while maintaining the original manufacturer's specifications. Compared to low-cost aftermarket alternatives, a used original component often offers better fit and predictable performance in the long term.

Before installation, a standard service procedure is recommended: checking the condition of the connector, wiring harness, and the socket in the steering knuckle, as well as verifying the correctness of the signal reading via computer diagnostics after installation.

Benefits of Using an Original ABS Sensor

Using an original ABS speed sensor in a Mercedes W221 offers a number of practical benefits:

• Factory Fit – no issues with cable length, plug type, or mounting position.
• Consistency with the control unit software – the sensor signal is in line with the parameters intended by the vehicle manufacturer.
• Reduced risk of ABS/ESP errors – correct wheel speed reading minimizes false messages and limp-home modes.
• Possibility of precise diagnostics – an original part facilitates data interpretation in service testers.

Professional Installation and Operational Tips

When replacing the ABS sensor in a Mercedes W221, it is worth paying attention to several technical aspects:

• thorough cleaning of the mounting socket from corrosion and dirt,
• checking the condition of the pulse ring on the hub or CV joint,
• correct routing of the cable, maintaining original mounting points,
• checking the wiring harness for chafing and insulation damage.

For users interested in a broader context of selecting and evaluating drivetrain components and their associated sensors, we recommend the guide article on purchasing used differentials, sensors, and drivetrain components, which helps to better understand the relationships between individual sub-assemblies.

Summary

Mercedes W221 ABS Sensor Rear Right Rear Right is a solution for drivers who want to restore the full functionality of the ABS system while maintaining the vehicle's original operating parameters. Its proper fit for the rear right axle, factory signal characteristics, and integration capability with the existing wiring make it a practical choice for brake system repairs on the W221 model.