I need to replace my o2 sensors for my audi a6. These are the codes that came up:

P0130 = o2 sensor circuit malfunction bank 1 sensor 1
And
P0150 = o2 sensor curciot malfucntion bank 2 sensor 2

Can someone tell me how many o2 sensors the car has? And also are both of those o2 sensors before the cataltitic convertoer or is one before and the other is after cat convertor. Thanks in advance.

2 before the converters and 2 after the converters. Total of 4. Bank 1 is passenger side and Bank 2 is the driver side. Sensor 1 is before sensor, and sensor 2 is after sensor.

my mistake the codes were bank 1 sensor 1 and bank 2 sensor 1. so i will replace both before cat converter. why does our car have 4 o2 sensors?

dual exhaust

o2 sensor pre-cat and post-cat on both

i also have the
P0130 = o2 sensor circuit malfunction..
Is it possible to this DIY or does it have to be professionally done?
Thanks

Definitely DIY, but you need some tools. O2 sensor socket and long extension with a swivel head. Also good to know someone with small hands and arms. I think I did a brief DIY for B1S1 sometime ago. Do a search. You should find it.