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

Vehicle applications include:
Audi A3
Audi S3
Audi A4
Audi A5
Other Volkswagen Group MQB/MLB diesel vehicles using 8W0907807B / 8W0907807H / 5WK97257

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 injection and reduce emissions.

Q2: Where is this sensor installed?
A2: It is installed in the exhaust aftertreatment system, typically upstream or downstream of the SCR catalyst depending on configuration.

Q3: Are 8W0907807B and 8W0907807H interchangeable?
A3: They are superseded or variant part numbers, but exact matching is still required due to calibration differences.

Q4: Is 5WK97257 compatible with OEM numbers?
A4: Yes, 5WK97257 is a common aftermarket cross-reference for this Audi NOx sensor family.

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