Fitment

Confirmed OE application based on cross-reference catalog data:

• Audi A8 D4 (4H chassis) 3.0 TDI / 4.2 TDI
• Audi Q7 (4L platform variants depending on engine code)
• V6 / V8 TDI diesel engines with SCR (AdBlue) emission systems

Fitment is based strictly on OE number matching.

Technical Description

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

It sends real-time data to the ECU to control SCR (Selective Catalytic Reduction) dosing strategy and maintain emissions compliance in diesel systems.

The sensor is part of the emissions monitoring system and is typically mounted in the exhaust line (pre or post SCR depending on configuration).

Symptoms / Fault Codes

Common symptoms of failure 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

• 4H0907807H
• 5WK97209 (Continental reference)
• Interchange family: 4H0907807D / 4H0907807E / 4H0907807M (varies by revision)

FAQ

What does this NOx sensor do?

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

Is this sensor vehicle-specific?

Yes. Compatibility is strictly determined by OE number matching.

Are similar 4H0907807 variants interchangeable?

Not always. Even small OE suffix differences usually indicate different calibration or system configuration.

What system is it used in?

It is used in VAG diesel SCR (AdBlue) emission systems on large Audi platforms.