1998 volvo s70, turbo. Every time the ac is on check engine light would come on, and it is p0131 (02 sensor). This is the only code it would give me and every time I reset it and turn the ac off I can drive for days without CE light coming on again. What is connection, what throws this code on? Btw. AC is fully charged and it is working fine, car runs fine, no problems.

 

That sounds strange they shouldn't be connected.
The only way I think they are connected is by the high pressure switch.Emmission stuff is on the circuit as well.But it is not the O2 sensors.