On my1999 A6 Avant quattro (74K miles) ,I have a check engine lighton and just got the following computer code from my friends diagnostic readed: P0432 - Main catalyst below threshold (bank2).

Does this mean the catalytic converter is bad or is it just a sensor? Are their 2 catylitic converters on this model? What does bank 2 mean? How do you determine which converter is bad if their are 2 of them?

Please advise.

 

This is most likely one of the O2 (Oxygen) sensors on the exhaust pipe. Bank 1 = passenger side, Bank2 =driver's sideThere are 2 sensors on each side, onein front ofand one behind the catalytic converter.
The other possibility is a faulty catalytic converter, which Audimay cover under the Federal 8 year emissions warranty.
https://www.audiforums.com/m_334156/tm.htm

 

I think that you have a bad 02 sensor. if the engine is out of tune up; excess fuel entering exhaust; oil or anti-freeze entering exhaust; bad spark plugs or spark plug wires; bad 02 sensor - are some of the usual signs why audi catalytic converter fails.. anyways, good luck and hope you fixed it soon.