what is the difference between heated and planer sensors and which one do i need for the rear sensor?
oxygen sensor on 2000 Honda Civic
The difference between the sensors are the way in which they operate. The oxygen sensor is the older technology but is still a commonly misused term to describe both. The rear sensor's primary function on all OBD2 cars is used to monitor catalytic converter efficiency and is an Oxygen sensor. The front sensor is used to measure combustion efficiency and on many newer cars is an air fuel ratio sensor or planer sensor which is more accurate and can be more expensive.