Mercedes-Benz A E W168 M166 W210 M111 Petrol Engine Crankcase Knock Sensor

Mercedes W168 M166 W210 M111 Knock Sensor is a precise component of the gasoline engine control system, responsible for reliable detection of knocking combustion in the front part of the power unit. Thanks to it, the engine control unit can continuously adjust the ignition timing, which contributes to stable operation, reduced risk of mechanical damage, and maintenance of proper performance. This solution is particularly important in vehicles in use, where both the safety of the power unit and predictable vehicle behavior under various load conditions are crucial.

Specifications and technical data

• SKU: A0031538928
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A0031538928
• Substitutable numbers: A0031538928, A 003 153 89 28
• Location on the vehicle: Front
• Fuel type: Petrol
• Category: Other Engine Parts

Function and Role of the Knock Sensor

The knock sensor in Mercedes models with M166 and M111 gasoline engines monitors engine block vibrations in the front area and transmits a signal to the control unit. Based on this, the control system can:

• detect knocking combustion in real-time,
• adjust ignition timing to current operating conditions,
• reduce the risk of overheating and excessive mechanical loads,
• maintain stable engine operation.

A properly functioning knock sensor directly impacts the durability of the power unit, as well as the consistency of performance under different loads and fuel qualities.

Intended for Gasoline Engines and Front-End Installation

The presented sensor is designed for gasoline engines and is installed in the front part of the power unit, which provides favorable conditions for registering characteristic vibrations associated with knocking combustion. This placement allows for:

• precise capture of unwanted vibrations at key points of the block,
• efficient communication with the factory engine control unit,
• compliance with the original ignition system architecture.

This allows the sensor to work with the factory wiring harness and engine structure, facilitating installation and subsequent diagnostics.

Characteristics as an Original Mercedes Part

As a part intended for Mercedes vehicles, the knock sensor has been designed to comply with the factory operating parameters of M166 and M111 units. This means that it:

• maintains appropriate sensitivity and signal characteristics for the given engine control unit,
• is structurally adapted to the intended mounting location,
• allows for the maintenance of factory engine protection strategies against knocking combustion.

Such adaptation promotes stable operation of the ignition system without the need for modifications to the wiring or control unit parameters.

Used Condition and Benefits of Using Parts from Disassembly

The offered sensor is a used part, which allows for economical repair of the knock control system while maintaining the original manufacturer's specifications. In many cases, using a tested part from disassembly is a reasonable compromise between cost and functionality, especially in vehicles used daily.

If you want to learn more about the advantages of using used components in premium brand cars, it is worth reading the article describing the practical aspects of such solutions – you can find it here: replacement of body parts with used parts and vehicle operational quality.

Technical Support and Additional Information

When selecting a knock sensor for a specific Mercedes model, it is crucial to match it to the type of gasoline engine and the power unit configuration. If in doubt, it is advisable to verify compatibility with the service documentation or factory part number to ensure proper cooperation with the control system.

If you are planning a comprehensive repair or upgrade of the engine area in your Mercedes and need other parts from the same group, such as sensors, wiring harnesses, or control modules, check the available parts in the Other Mercedes category.

For a comparison of solutions used in different brands and engine versions, including sports variants, you can also refer to the comparative material on power units and accessories – you can find it here: Audi RS vs. other models – what lies under the hood and chassis?.