Audi S6 C7 S7 4G Lambda Probe Oxygen Sensor 4 Pin Cyl.1-4 4.0 Petrol 4H0906265B

The Audi S6 C7 S7 4G 4.0 Petrol Lambda Sensor 4 Pins Cyl. 1-4 is a precise exhaust system component from the Lambda Sensors and O2 Sensors group, specifically designed for V8 petrol engines in sporty Audi models. It is responsible for accurate exhaust gas composition measurement for cylinders 1–4, enabling the engine control unit to stably regulate the fuel-air mixture and maintain optimal engine performance. This is a used original component, intended for drivers who want to restore correct fuel system operation without compromising compatibility.

Specifications and technical data

• SKU: 4H0906265B
• Mark: Audi
• Condition: Used
• OEM Part Number: 4H0906265B
• Substitutable numbers: 4H0906265B, 4H0 906 265 B, 0 258 010 327, 0258010327
• Fuel type: Petrol
• Category: Oxygen Sensors

Function of the Lambda Sensor in a 4.0 Petrol Engine

The lambda sensor serving cylinders 1–4 in the 4.0 petrol engine is responsible for continuous monitoring of the mixture composition in the first cylinder bank. Based on the sensor's signal, the control unit adjusts the fuel dose, which results in:

• stable engine operation across the full RPM range,
• efficient operation of the exhaust gas purification system,
• maintaining fuel consumption at the manufacturer's specified level,
• reducing the risk of exhaust component overheating due to an overly rich mixture.

The configuration for cylinders 1–4 is particularly important in V-engines, where each cylinder bank requires separate, correctly functioning exhaust gas composition monitoring.

Construction and Connector Parameters – 4 Pins

The presented lambda sensor uses a four-pin connector, meaning both the signal path and the heater circuit are integrated into a single housing. This design allows for:

• faster achievement of operating temperature after engine start,
• a stable measurement signal from the initial phase of engine operation,
• reliable and interference-free communication with the control electronics.

This enables the engine control system to precisely respond to changes in load and driving conditions, which is important for both daily use and dynamic driving of S6 and S7 models.

Intended for Audi S6 C7 and S7 4G Models

The offered sensor has been developed for sporty Audi models from the S6 C7 and S7 4G family equipped with the 4.0 petrol engine. Using a dedicated component from the same design group as the factory part ensures:

• compatibility with the factory engine control unit software,
• correct operating parameters in comfort and sport modes,
• consistency with other sensors in the exhaust system.

This solution is particularly beneficial for diagnosing errors related to the fuel-air mixture, uneven engine running, or improper catalytic converter operation.

Condition, Installation, and Selection by Numbers

The component is a used part obtained from disassembly, offering a reduced repair cost while maintaining original specifications. Before installation, standard service procedures are recommended: check the wiring harness, connectors, and verify any engine control unit errors. It is advisable to base the sensor selection on the OEM number and interchange numbers to ensure full compatibility with the specific equipment version.

If you are planning a comprehensive repair or upgrade of the engine area in your Audi and require other components from the same group, such as additional pre-catalytic converter sensors, post-catalytic converter sensors, or O2 sensors for the second cylinder bank, check the available parts in the Audi Lambda Sensors and O2 Sensors category.

Technical Support and Selection of Used Electronics

When replacing a lambda sensor, correct matching by part number and consideration of the specific control electronics in the vehicle are crucial. A practical guide provides an overview of sensor and module selection principles, including the importance of OEM numbers, hardware and software compatibility, and examples of typical installation issues – details are described in the article Used Automotive Electronics Onboard – Why Choose Second-Hand ECU Modules and Sensors?.