Audi A8 D4 Lambda Probe Oxygen Sensor Cylinder 1-4 4.2 TDI CDSB 4H0906262D

Audi A8 D4 Lambda Probe Oxygen Sensor Cylinder 1-4 4.2 TDI CDSB is an original exhaust system component designed to support cylinders 1–4 in the 4.2 TDI CDSB diesel engine. As part of the Lambda probes and O2 sensors group, it is responsible for the precise measurement of oxygen content in exhaust gases, which allows the engine control unit to ensure stable, efficient, and safe operation of the powertrain. This used OEM component is a sensible choice for professional repair or diagnostics of the injection and exhaust system in an Audi A8 D4.

Specifications and technical data

• SKU: 4H0906262D
• Mark: Audi
• Condition: Used
• OEM Part Number: 4H0906262D
• Substitutable numbers: 4H0906262D, 4H0 906 262 D
• Category: Oxygen Sensors

Purpose and function in the exhaust system

The presented lambda probe operates in the exhaust stream of the 4.2 TDI CDSB engine, monitoring the air-fuel ratio for cylinders 1–4. Based on its signal, the engine control unit adjusts the fuel dosage, which affects:

• the stability of the powertrain across the full load range,
• the maintenance of the correct mixture under both city and highway driving conditions,
• the efficiency of the exhaust gas treatment system (catalytic converter, diesel particulate filter),
• the reduction of smoke and harmful exhaust emissions.

Thanks to this, the Audi engine control system can operate in an optimized mode, which translates into smooth operation, throttle response, and predictable fuel consumption.

Benefits of using an original Audi lambda probe

Choosing an original lambda probe dedicated to the Audi A8 D4 4.2 TDI CDSB provides a number of practical advantages compared to universal replacements:

• a secure fit for the electrical harness and mounting thread in the exhaust system,
• correct signal parameters for the factory engine control unit,
• stable operating characteristics at typical 4.2 TDI engine exhaust temperatures,
• reduced risk of diagnostic errors and warning lights.

For the user, this means more predictable diagnostics, easier system tuning, and a lower risk of recurring faults related to incorrect exhaust gas composition readings.

Condition, origin, and service application

The offered lambda probe comes from disassembly and is an original Audi brand component. A used component of this type is frequently chosen by professional workshops for:

• clearing errors related to incorrect mixture composition,
• repairs following exhaust or injection system failures,
• diagnosing power, fuel consumption, and emission issues,
• comprehensive maintenance of the 4.2 TDI CDSB engine in the Audi A8 D4.

Due to its factory origin, the part fits well into the vehicle's existing electrical and mechanical architecture, which facilitates installation and reduces vehicle downtime at the service center.

Installation and operational recommendations

When replacing the lambda probe in an Audi A8 D4, it is worth paying attention to a few technical aspects:

• checking the condition of the thread in the manifold/exhaust section and using appropriate assembly paste designed for sensors,
• routing the cable while maintaining factory mounting points, away from excessive heat sources,
• performing adaptation or clearing error codes in the engine control unit after installation,
• checking other exhaust and intake system components for leaks.

This approach allows you to fully utilize the potential of a functional lambda probe and limits the risk of secondary faults resulting from other issues in the system.

If you are planning a comprehensive repair or upgrade of the engine area in your Audi and need other elements from the same group, such as additional probes, exhaust gas temperature sensors, or mixture composition sensors, check the available parts in the Audi Lambda probes and O2 sensors category.

Used electronics and sensors – when is it a good choice?

In the case of measuring elements such as a lambda probe, many users consider using parts from disassembly. With proper verification and selection for a specific engine version, this can be an economical and technically sound solution. If you want to learn more about the selection of used electronic components in a car, practical tips can be found in the article The second life of electronics – when is it worth choosing used engine control units, comfort modules, and parking sensors?.