are Oxygen sensor and Tank Ventilation errors related?
 

"service engine soon" light, checked codes and had tank ventilation valve and Oxygen sensor errors. Cleared errors and ordered 4 new O2 sensors (about due with 90k on second set).
Error came back -but this time when I checked only "tank Ventilation valve" was present.
I did try re-setting gas tank cap after first Service engine soon light.

away from home and using most basic INAP program on my laptop.

Can a bad 02 sensor affect tank ventilation also or should I replace that too.

thanks!

You likely had two different problems going on, so now the O2 sensor issue is repaired but the vent valve issue remains. You will have to do some more diagnosing in the way of a smoke test to see if there is a leak in the evap system or if the valve itself is actually bad.

You are mis interpreting the code. You have a faulty ventilation valve. There is one at the left side rear inner wheel well. I believe its a small electric valve that communicates with the DME and if faulty sets off the code.

Thanks!
I have not changed the O2 sensors - but will continue with that replacement as they are at the end of there life.
It just seems too coninsidential that 2 error triggered the service light at the same time without being related??