9805940

9805940 is a component from the Engine sensors and switches group, designed for precise cooperation with the engine control system. It is responsible for stable crankshaft position readings, which translates into smooth engine operation and correct injection synchronization in popular 1.9 TDI units.

Specifications and technical data

• SKU: 9805940-1
• Mark: Volkswagen
• Condition: Used
• OEM Part Number: 9805940
• Substitutable numbers: 9805940
• Category: Engine Sensors & Switches

Purpose and function of the crankshaft sensor

The offered sensor is dedicated for use in the 1.9 TDI diesel engine installed in the Volkswagen Passat B6 model, in the engine block area. Its task is to generate a crankshaft position and rotational speed signal, which the engine control unit uses for:

• precise determination of fuel injection timing,
• idle speed control,
• correct engine starting,
• monitoring engine operation for error diagnostics.

A functional crankshaft sensor reduces the risk of starting problems, engine stalling, or rough running at low speeds, which directly affects the comfort of using the vehicle.

Benefits of using an original Volkswagen component

The element comes from the Volkswagen parts group, which means maintaining factory operating parameters and full compatibility with the engine control unit software. In practice, this translates into:

• a stable signal for the engine control system,
• proper cooperation with the factory electrical installation,
• proper fit to the mounting socket in the engine block,
• reduced risk of errors appearing in the controller's memory.

By maintaining the original operating characteristics, the sensor supports the maintenance of correct combustion parameters and the refinement of the 1.9 TDI unit, which is particularly important when operating in city and highway conditions.

Condition, installation, and service application

The offered crankshaft sensor is an aftermarket component, which allows for economical repair of the engine control system while maintaining appropriate quality. It works well both as a replacement for a damaged sensor and as an element used preventively during major service work within the engine block.

Due to its location in the engine block, sensor replacement is often performed in parallel with other maintenance activities, such as work on the timing belt or seals, which allows for reducing vehicle downtime and optimizing labor costs.

Diagnostic support and technical knowledge

In case of problems with starting, jerking, or sudden engine stalling, it is worth performing a full diagnostic of the injection and turbocharging system, as an incorrect reading from the crankshaft sensor may overlap with other faults. To expand your knowledge about the operation of modern diesel engines and the impact of accessories on performance, the following article will be helpful: The second life of the Mercedes OM642 engine – how injectors and a turbocharger restore the power of a 3.0 V6 CDI, which discusses the relationships between control, injection, and turbocharging.

Related elements from the same group

If you are planning a comprehensive repair or upgrade of the engine area in your Volkswagen and need other elements from the same group, such as temperature sensors, camshaft position sensors, or switches related to engine operation, check the available parts in the Volkswagen engine sensors and switches category.

Summary

9805940 is a practical service solution for users of popular TDI units, allowing for the restoration of correct engine synchronization and limiting typical problems with starting or rough operation. Choosing an element from the Volkswagen group ensures proper fit to the engine block and compatibility with the factory controller, which facilitates diagnostics and vehicle operation after repair.