Fitment

Confirmed OE application based on catalog cross-reference data:

• Audi A4 B8 (8K chassis) 2.0 TDI
• Audi A5 2.0 TDI (8T / 8F platform variants)
• Audi Q5 (8R) 2.0 TDI
• SCR (AdBlue) diesel emission systems

Fitment is strictly based on OE number matching: 8K0907807D / 5WK96641B

Technical Description

This NOx sensor is used in diesel exhaust aftertreatment systems to measure nitrogen oxide (NOx) concentration in exhaust gases.

It transmits real-time data to the engine control unit (ECU) to regulate SCR (Selective Catalytic Reduction) dosing strategy and ensure emissions compliance in diesel vehicles equipped with AdBlue systems.

The sensor is part of the emissions monitoring system and is typically mounted in the exhaust stream (upstream or downstream depending on configuration).

Symptoms / Fault Codes

Common symptoms of a failing NOx sensor may include:

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

OE / Part Numbers

• 8K0907807D
• 5WK96641B

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.

Is this sensor vehicle-specific?

Yes. Compatibility is strictly determined by OE number matching. Even small suffix differences may indicate a different revision.

Can similar Audi NOx sensors be interchangeable?

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