Mercedes W169 W245 OM640 CDI Diesel Air Flow Sensor Mass Meter A6400900407

Mercedes W169 W245 OM640 CDI Diesel Air Flow Sensor Mass Meter is a precision intake system component responsible for accurately measuring the amount of air intake in diesel engines. A properly functioning mass air flow sensor ensures stable engine operation, optimal combustion, and predictable throttle response. By choosing this item from the Air and fuel intake sensors group, you are investing in a proven, factory-spec design tailored to the specifics of the OM640 CDI engine.

Specifications and technical data

• SKU: A6400900407
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6400900407
• Substitutable numbers: A6400900407, A 640 090 04 07
• Fuel type: Diesel
• Category: Air Intake & Fuel Sensors

Function of the mass air flow sensor in the OM640 CDI diesel engine

In diesel engines, precise fuel metering based on the amount of air drawn into the intake manifold is crucial. The mass air flow sensor in Mercedes W169 and W245 models with the OM640 CDI engine transmits accurate air mass information to the engine control unit, which allows for:

• maintaining stable idle speed,
• correct fuel dosing across the entire load range,
• reducing smoke emissions and power loss,
• efficient cooperation with the exhaust gas recirculation system and exhaust aftertreatment systems.

As a result, the engine runs smoothly, and throttle response remains predictable both in city traffic and during dynamic acceleration.

Benefits of using an original air intake sensor

Items from the Air and fuel intake sensors group in Mercedes vehicles are designed for the specific flow characteristics of a given engine. Using the correct mass air flow sensor in W169 and W245 models with the OM640 CDI unit allows you to maintain:

• calibration consistency with the engine control unit,
• proper operation across the full range of operating temperatures,
• appropriate response to rapid load changes,
• stable air-fuel mixture parameters during long-term operation.

This is particularly important in modern diesel engines, where even minor deviations in air flow measurement can result in control unit errors, power loss, or increased fuel consumption.

Used condition – a conscious choice for economical service

The offered mass air flow sensor is in used condition, which represents a reasonable compromise between repair costs and maintaining proper engine performance parameters. For many Mercedes W169 and W245 users, this is a practical solution for:

• diagnosing power issues and rough engine operation,
• maintenance of older vehicles,
• optimizing repair costs while retaining parts with factory specifications.

By choosing a used, original mass air flow sensor, you avoid the risks associated with cheap replacements of uncertain measurement characteristics, which directly impacts the refinement of the diesel engine.

Integration with the intake and fuel system

The mass air flow sensor in a diesel engine works directly with the fuel injection system and the engine control unit, which is why its correct operation is essential for the entire fuel supply system. To better understand the relationship between air measurement and fuel dosing, it is worth checking out our guide on the construction and operation of the fuel system, injectors, pumps, and fuel tank, which discusses diagnostics and component selection based on OEM numbers.

Expanding service within air and fuel intake sensors

If you are planning a comprehensive repair or upgrade of the engine area in your Mercedes and need other items from the same group, such as additional pressure sensors, air temperature measurement elements, or components related to fuel dosing, check out the available parts in the Mercedes air and fuel intake sensors category.

Summary

Mercedes W169 W245 OM640 CDI Diesel Air Flow Sensor Mass Meter is a technically matched intake system component designed for diesel engines in compact Mercedes models. Precise air mass measurement supports correct fuel dosing, stable engine operation, and predictable performance. For users looking for an economical yet specification-compliant service solution, a used mass air flow sensor is a practical choice that helps restore the correct operating parameters of the OM640 CDI engine without overstretching the budget.