A few days ago my service engine soon or SES light came on with a P0050 OBDII code. After clearing it just two starts later it came back so with 80,000 miles on the car I just decided to replace both O2 sensors.


Tools:
22mm Wrench
PB Blaster
(2) Bosch 13477 or 13559 Oxygen Sensors (O2)
See this post for details

Working on a cool / cold engine soak both old sensors with a quick shot of PB blaster and let them sit for 20min.

I started with removing the upstream sensor first:


Then the downstream sensor:


Note the picture above shows there is enough room to work a wrench should you not have an O2 socket.

Installation of the new sensors is just the reverse the removal of the old ones. Tighten them the same way your would tighten a spark plug.