O2 Sensor: Description

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

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

Fig 1: Identifying O2 Sensor Upstream 1/1 4 Cylinder

Courtesy of DAIMLERCHRYSLER CORP.

Fig 2: Identifying O2 Sensors 2.7L

Courtesy of DAIMLERCHRYSLER CORP.

Fig 3: Identifying O2 Sensor Downstream 2/1 4 Cylinder

Courtesy of DAIMLERCHRYSLER CORP.