What is TWC (RE Oxygen Sensor)?

[gschotland]

Looking through the PO's service recs I found "Replaced O2 sensor for Bank #1 ahead of TWC." Could find anything in this forum or in the Bentley manual. I did see TWC mentioned on another forum, but no explanation of what it is.

What is the TWC? I want replace the 3 other O2 sensors, so I need to know whether to buy 2 pre-cat & 1 post-cat or vice versa.

Thanks,

Gary
'02 S

[sd_boxster]

twc = the catalytic converter (shorthand for three-way catalytic converter).

[gschotland]

Ah, OK. Makes sense, kind of. I knew the "c" was for cat, but couldn't for the life of me get the "tw" part.

Thanks,

Gary