Fitment

Based on OE catalog cross-reference data, 4N0907807B / 4N0907807 is used in Volkswagen Group MLB Evo / D5 platform diesel SCR (AdBlue) systems.

Common applications include:

• Audi A8 (4N platform) 3.0 TDI / 4.0 TDI diesel variants
• Audi Q7 (4M facelift / MLB Evo diesel configurations)
• Audi Q8 (MLB Evo diesel variants depending on engine code)
• Volkswagen Touareg (CR / MLB Evo diesel variants)
• SCR (AdBlue) exhaust aftertreatment systems

Fitment is strictly based on OE number matching: 4N0907807B

OE cross-reference data shows this sensor family is widely used across Audi A8 (4N) and related MLB Evo diesel platforms.

Technical Description

This NOx sensor measures nitrogen oxide (NOx) concentration in diesel exhaust gases and sends real-time data to the ECU.

It is part of the SCR (Selective Catalytic Reduction) system and controls AdBlue dosing strategy to reduce emissions and ensure Euro 6 compliance.

The sensor is an integrated electronic module designed for high-temperature exhaust environments and continuous emissions monitoring in modern VAG diesel platforms.

Symptoms / Fault Codes

Common symptoms of failure include:

• Check engine light
• P2200 / P229F fault codes (system dependent)
• SCR / AdBlue system warning
• Reduced engine performance (limp mode)
• Increased emissions

OE / Part Numbers

• 4N0907807B
• 4N0907807
• Related OE family variants (4N0907807F / J / M depending on revision and position)

FAQ

What does this NOx sensor do?

It measures nitrogen oxide levels in diesel exhaust and sends data to the ECU for SCR emission control.

Which vehicles use this part?

It is commonly used in Audi A8 (4N platform) and other MLB Evo diesel models such as Q7, Q8, and Volkswagen Touareg depending on engine configuration.

Is this sensor vehicle-specific?

Yes. It is strictly matched by OE number. Even small suffix differences (B / F / J / M variants) can indicate different ECU calibration or sensor position (upstream/downstream).

Can similar NOx sensors be used instead?

Not recommended. NOx sensors are ECU-calibrated components and must match exact OE specification.