Mercedes S212 W212 ABS Sensor Wheel Speed Sensor Front Right O/S A2129053403

Mercedes S212 W212 ABS Sensor Wheel Speed Sensor Front Right O/S is a high-precision braking system component responsible for accurately reading the rotational speed of the wheel on the front right axle. By working in conjunction with the ABS and traction control systems, the sensor supports vehicle stability, reduces braking distance in critical situations, and improves driving safety. This solution is designed for users who expect proven, factory-standard mounting geometry and a reliable measurement signal.

Specifications and technical data

• SKU: A2129053403
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2129053403
• Substitutable numbers: A2129053403, A 212 905 34 03
• Location on the vehicle: Front, Right
• Category: ABS Speed Sensors

Purpose and function of the ABS speed sensor

The offered component belongs to the ABS speed sensor category and is dedicated to the braking system of Mercedes S212 / W212 series vehicles. Mounted on the front right side, it monitors wheel rotational speed and transmits the signal to the ABS control unit and electronic stability control systems. A properly functioning sensor allows for:

• precise distribution of braking force on individual wheels,
• reduction of wheel slip during emergency braking,
• more stable vehicle handling on slippery surfaces,
• correct operation of driver assistance systems.

Design, fitment, and installation

The sensor has been specifically designed to work with the hub and front braking system on the right side of S212 / W212 models, ensuring proper positioning relative to the impulse ring. The appropriately shaped housing and mounting socket facilitate installation in the factory mounting point without the need for modifications. Thanks to the preservation of the original mounting geometry, it is possible to achieve:

• stable seating of the sensor in the steering knuckle or caliper bracket,
• maintenance of the correct operating gap relative to the ring,
• reduction of the risk of measurement signal interference.

Benefits of using an original Mercedes sensor

Using a sensor dedicated to a specific axle and side of the vehicle translates into consistent operation of the entire ABS system. Factory fitment for the S212 / W212 platform minimizes the risk of installation errors and electrical compatibility issues. In practice, this means:

• a lower probability of ABS errors appearing on the dashboard,
• a stable wheel speed signal across the full range of driving speeds,
• proper cooperation with active safety systems.

This pre-owned component allows for an economical repair of the braking system while maintaining the manufacturer's original specifications, which is particularly important for the advanced electronic systems used in Mercedes vehicles of this generation.

Application in the drivetrain and diagnostics

The wheel speed sensor is significant not only for the ABS itself but also for the operation of the drivetrain and traction control systems. An incorrect reading of one wheel's speed can cause:

• malfunction of traction control and electronic stability control,
• disturbances in the operation of the automatic transmission (where it utilizes wheel speed signals),
• increased wear of braking system components.

To better understand the impact of sensors on the durability and proper operation of the drivetrain, it is worth checking out our guide on used drivetrain components: Second-hand differential – what you need to know about used differentials, sensors, and drivetrain systems.

Selection of other Mercedes ABS speed sensors

If you are planning a comprehensive repair or upgrade of the braking zone in your Mercedes and need other components from the same group, such as sensors for other wheels, additional front axle sensors, or rear axle sensors, check out the available parts in the Mercedes ABS speed sensor category.