FITMENT
Compatible with Audi diesel vehicles equipped with SCR (Selective Catalytic Reduction) AdBlue emission systems requiring NOx monitoring.
Common applications include:

• Audi A4 (B9 / 8W platform diesel SCR variants)
• Audi A5 (F5 platform diesel SCR variants)
• Audi S5 (diesel SCR-equipped models where applicable by region)
• Related Volkswagen Group MLB Evo diesel platforms

Using reference numbers:

• 8W0907807Q
• 8W0907807E
• 8W0907807L
• 5WK97434 (Continental/VDO sensor family cross-reference)

This NOx sensor is part of the SCR exhaust aftertreatment system, responsible for monitoring nitrogen oxide emissions and controlling AdBlue dosing for Euro 6 compliance.

FAQ
Q1: What is the function of this NOx sensor?
A1: It measures nitrogen oxide (NOx) levels in the exhaust system and sends data to the ECU to regulate AdBlue injection and reduce emissions.

Q2: Where is it installed?
A2: It is installed in the SCR exhaust system, typically before or after the catalytic converter depending on vehicle configuration.

Q3: What are symptoms of failure?
A3: Check engine light, SCR/AdBlue warnings, NOx sensor fault codes, reduced engine power, or limp mode activation.

Q4: Are 8W0907807Q / E / L interchangeable?
A4: These are revision-level variants within the same Audi SCR sensor family. Compatibility depends on VIN, ECU calibration, and emission system version.