Can anyone help me with error codes?

[wahoo]

I am receiving (4) codes on my '00 A6 4.2:
17539 - O2 sensor, B2S1 Internal resistance too high.
17521 - P1131 - 35-10 - Intermittent
17831 - P1113 - 35-00
17819 - P1411 - 35-00

Thanks in advance...