One of the ways emissions are controlled by the C4 UrS-car AAN ECU is storing and then recovering evaporative emissions from the fuel tank and then bleeding them from a storage canister into the intake manifold via the N80 evaporative emissions control valve (Solenoid valve PN 034133517). This info might be of interest:







There is possibility that a failed N80 will throw a code (CEL). This info would be interpreted as:

4343 (Blink Fault Code), 01247 VAG1551/2 Fault Code Number
Carbon Canister Solenoid, Evaporative Canister Purge Valve (N80),
Open or short circuit, +12V supply circuit breaker or fuse open?
Symptom: Poor response in part of load range, fuel odors, idle speed or quality may be affected
(Reference SJM Autotechnik)

If there are issues, you could try cleaning and lubing the N80 solenoid valve. Otherwise, off to the dealer for a new part. It's very common across the 1988 to 1997 Audi range so it should NOT be too hard to find, even used.

This will be on the exam.