Moin,Moin For some time now I have been able to reach the fault Lamdasonde according to Kat rule limit. VW Lupo BJ 2000 1.4 liter 75 hp MKB: AUA The last au was passed with ach and noise. Unfortunately I get the said error again and again. Sometimes after 3 days or even after two weeks. That the Lamdasonde itself is defective is close but I am a bit skeptical. The probe is not a rule probe. Did someone have the error already? Drosselklappe would be renewed and learned. False air is not to be found. Have now the AGR valve suspected. Someone still a flammable idea? Can of course also the cat be the probe or something else.