Fitment
Compatible with Volkswagen Group Euro 6 diesel emission systems (SCR / AdBlue)

Vehicle applications include:
Audi A4
Audi A5
Other VW Group MLB platforms using OEM part numbers 8W0907807A / 8W0907807G / 5WK97259

FAQ

Q1: What is the function of this NOx sensor?
A1: It measures nitrogen oxide levels in diesel exhaust and sends data to the SCR system to control AdBlue (DEF) dosing and reduce emissions.

Q2: Are 8W0907807A, 8W0907807G, and 5WK97259 interchangeable?
A2: They are OEM and aftermarket cross-reference numbers within the same sensor family, but exact matching is still required due to calibration differences.

Q3: Where is this sensor installed?
A3: It is installed in the exhaust aftertreatment system, typically upstream or downstream of the SCR catalyst depending on vehicle configuration.

Q4: Is this used only in Audi A4/A5?
A4: It is primarily used in Audi A4 and A5 B9 diesel SCR systems but may also appear in other VW Group MLB diesel vehicles.

Q5: What are common failure symptoms?
A5: Engine warning light, AdBlue/SCR faults, NOx sensor signal errors, or limp mode.