2001 volkswagen jetta GLS 1.8T DTC code shows Catalyst efficiency low on threshold does anyone know what could be wrong cause volkswagen dealer told me that the catalyst converter needs to be replaced?

Answer 1

replace o2 sensor behind cat.converter first, you probably do need a catalyst, the emission warranty for that is 8 years or 80,000 miles minimum and may be longer on some models so if you have less than 80,000 miles and the date car was originally purchased on is less than 8 years ago the dealer will replace it at no cost to you.