Mercedes S204 W204 ABS Sensor Brake Caliper Rear Left N/S Cable A2045404605

The Mercedes S204 W204 Left Rear ABS Brake Pad Wear Sensor is a safety system component responsible for precisely monitoring the condition of brake pads and the operation of the ABS system on the rear left axle. Thanks to its factory fitment for Mercedes W204/S204 models, it ensures stable cooperation with the vehicle's electronics and correct signal interpretation by the control unit. A used component allows for an economical yet technically sound repair of the braking system.

Specifications and technical data

• SKU: A2045404605
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2045404605
• Substitutable numbers: A2045404605, A 204 540 46 05
• Location on the vehicle: Rear, Left
• Category: ABS Speed Sensors

Function and Role of the ABS Speed Sensor

The presented component belongs to the ABS Speed Sensor category and operates in close proximity to the wheel hub and the pulse ring. It is responsible for generating the wheel rotational speed signal, which is then analyzed by the ABS/ESP control unit. A properly functioning sensor enables:

• effective prevention of wheel lock-up during braking,
• stable operation of assistance systems (ABS, ASR, ESP),
• precise detection of speed differences between wheels,
• monitoring of brake pad wear on the rear left axle.

Intended Use and Vehicle Placement

The ABS Speed Sensor is designed for installation on the rear left side of Mercedes vehicles from the W204/S204 family. This placement on the vehicle ensures proper cable routing, appropriate distances from moving parts, and correct positioning relative to the pulse ring. This allows the control unit to receive a stable, clear signal, which translates into predictable vehicle behavior during braking and acceleration.

Benefits of Using an Original Mercedes Sensor

Using an original sensor in the ABS system of a Mercedes W204/S204 allows for the preservation of the braking system's original operating parameters. Key advantages include:

• Full Electrical Compatibility – correct signal and resistance values, compliant with control unit requirements.
• Appropriate Mounting Geometry – matched mountings and cable length, reducing the risk of mechanical damage.
• Stable operation across a wide range of temperatures and road conditions.
• The ability to restore proper ABS system function without interfering with the wiring harness.

Product Condition and Service Application

The offered sensor is a used component, which helps reduce repair costs while maintaining proper system operating parameters. This type of component is particularly useful for:

• routine repairs after sensor failure or cable damage,
• comparative diagnostics for ABS operational issues,
• restoring braking system functionality in fleet and private vehicles.

Before installation, a standard check of the electrical system and the connection socket is recommended to ensure proper contact and avoid signal interference.

If you are planning a comprehensive repair or upgrade of the braking area in your Mercedes and need other components from the same group, such as sensors for other wheels, signal cables, or components that work with the ABS system, check the available parts in the Mercedes ABS Speed Sensor category.

Drivetrain Safety and Diagnostics

A functional ABS sensor directly impacts driving safety, as well as the proper operation of the drivetrain and stability control systems. In case of errors related to wheel speed readings or improper operation of assistance systems, it is worth seeking expert advice. Extended information on the diagnostics of sensors and drivetrain components can be found in the guide Used Differentials – What You Should Know About Used Differentials, Sensors, and Drivetrain Systems, which helps in consciously selecting and evaluating used components.