I've just bought an A6 1.9 tdi in the U.K. I recently changed the air filter to a k and n free flow replacement filter. Now the emmission control light has come on and the roadside assistance bloke said that the engine coolant sensor was faulty, take it in and get it fixed under the warranty. Does anyone know if this filter will affect the warranty? Will audi say "aaahhhhh yeah, but you changed the filter and that made the sensor go nuts."...........any help much appreciated.

 

a K&N would effect the coolant temp sensor, don't think it would effect the warranty either unless the guy is wrong on his diagnosis and say it was the air flow sensor or MAF sensor then they might take a different view of that mod (it is known for that type of air filter to give issues) but that would only effect a new cars warranty

 

It has been noted in this forum that over oiling the K&N can cause problems.

 

es[ecially if you don't give it time to dry (18-24 hours), after oiling, before installing it.