That is the oxygen sensor screwed into the downstream side of the catalytic converter.That is the oxygen sensor screwed into the downstream side of the catalytic converter.
4 sensors total. 2 upstream on either side of exhaust manifold, 1 left side downstream, 1 right side downstream.
Downstream O2s are on the outlet side of the catalytic converter(s).
On a Ford Expedition : Bank 1 , Sensor 2 ( downstream ) is the sensor for the passenger side of the engine Bank 2 , Sensor 2 ( downstream ) is the sensor for the drivers side of the engine So in short the answer is from the ( drivers seat )
From underneath car there about 2' apart on either side of converter. Upstream is much harder then the downstream which is easy
ther are 2 oxygen sensors, an upstream and a downstream . The upstream is on driver side of engine exhaust and the downstream is back of catylitic converter agin on exhaust pipe.
It is after the catalytic onverter on the same side of the engine as cylinder #1.
Upstream is an O2 sensor located between the engine and the catalytic converter. Downstream is one located behind the converter.
drivers side of engine , after catalytic converter ( downstream )
drivers side of engine , downstream from catalytic converter
Downstream
Bank 1 = Cylinder 1/Drivers Side Bank 1 Sensor 1 = Upstream (before cat) Drivers Side Bank 1 Sensor 2 = Downstream (after cat) Drivers Side Bank 2 Sensor 1 = Upstream (before cat) Pass Side Bank 2 Sensor 2 = Downstream (after cat) Pass Side