O2 Sensor: Description

The upstream oxygen sensor threads into the outlet flange of the exhaust manifold. See Fig 4.Fig 1.

Fig 1: Upstream Heated Oxygen Sensor

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1 - OXYGEN SENSORS

2 - EXHAUST MANIFOLD

The downstream heated oxygen sensor threads into the system depending on emission package. See Fig 2. Federal package the O2s is mounted after the catalytic convertor, LEV package the O2s is mounted mid catalytic convertor, ULEV package is mounted between the catalytic convertor. See Fig 3.

Fig 2: Downstream Heated Oxygen Sensor

Courtesy of DAIMLERCHRYSLER CORP.

Fig 3: Heated Oxygen Sensor Systems

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1 - CATALYTIC CONVERTER (LEV EMISSION)

2 - CLOSE-COUPLED CATALYTIC CONVERTER (ULEV EMISSION)

3 - UNDER-FLOOR CATALYTIC CONVERTER (ULEV EMISSION)

4 - OXYGEN SENSORS

5 - OXYGEN SENSOR

Fig 4: NGK O2 Sensors

Courtesy of DAIMLERCHRYSLER CORP.