cat efficiency and secondary airflow

[olliebgollie]

i have been getting a DTC occasionally. it is 16806.p0422, cat efficiency below threshhold. i have a feeling i am not alone from reading other forums. anyone have an idea what could be causing this besides a tired cat? my car has 96k (2000 passat, 1.8L, ATW).
Also, should the secondary air pump be operating on every cold start? mine does not. i live in S.E. Pa, and this system does not always operate during cold starts (first start of the day in January when the car is cold soaked for example). could this be causing my first problem?

[dlsolo]

Sounds like the CAT has finally given up.

As for the SAI pump, yes, it should be.  If you need to replace it, you should be able to find one going for REALLY CHEAP on some of the VW/Audi forums.  Most people, to include myself, that theirs out and chuck them... 

[olliebgollie]

thanks for the info. about the cat - there was a big discussion on vortex in 2003 about this. some said the code was caused by exhaust gases leaking past the downstream 02 sensor. i don't know how this could happen and i don't believe they were talking about stock equipment. i did however have the tubo replaced recently, and the code popped up after the new turbo. does this change anything?
i get another code now. 16825,P0441 evaporative emission system: incorrect purge flow. at first i thought it was because i neglected to replace the gas cap after fueling. anyone have any ideas about this code?