So I got a P0136 code the other day --- Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2). I cleared the code, but it came back a week later. A quick look with my scan tool shows that the rear O2 sensor is dead. The output is stuck at 0.00 Volts. I crawled under the car and took a look. The wiring is OK but the element part of the sensor is very corroded and it moves if I wiggle it. I could easily break it off completely with my fingers. My concern is that it's on top of the exhaust pipe and kind of hard to get at. There doesn't seem to be a way to get an impact gun on it. Has anyone replaced their rear H02S? If so, how did you get it out. Is it easy to remove with a wrench? And, where is the connector for the sensor. I traced the wires back from the top of the sensor and they disappear in a wiring harness. Usually sensors have a pigtail with the connector on the end of it.