O2 Sensor: Description

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

Fig 1: Locating Upstream Heated Oxygen Sensor 1/1

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The downstream heated oxygen sensor threads into the system depending on emission package (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 (Fig 3).

Fig 2: Locating Downstream Heated Oxygen Sensor 1/2

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Fig 3: Identifying Heated Oxygen Sensor Systems

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Fig 4: Identifying NGK O2 Sensors

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