O2 Sensor: Description

The upstream O2 sensors are in the exhaust system in the exhaust manifold collector area before the upstream catalytic converter (Fig 1 ).

Fig 1: Identifying 2/1, 2/2, O2 Sensors

Courtesy of DAIMLERCHRYSLER CORP.

The downstream O2 sensors are in the exhaust system in between the catalytic converters (Fig 1 ).