O2 Sensor: Description

The upstream oxygen sensor threads into the outlet flange of the exhaust manifold (Fig 1) or (Fig 2).

Fig 1: Sensor Upstream 1/1 4 Cylinder

Courtesy of DAIMLERCHRYSLER CORPORATION

Fig 2: O2 Sensors 2.7L

Courtesy of DAIMLERCHRYSLER CORPORATION

The downstream heated oxygen sensor threads into the outlet pipe at the rear of the catalytic convertor (Fig 3).

Fig 3: O2 Sensor Downstream 2/1 4 Cylinder

Courtesy of DAIMLERCHRYSLER CORPORATION