Concorde V6-2.7L VIN R (1998)
Fig 12 Upstream Heated Oxygen Sensor
The upstream oxygen sensor threads into the outlet flange of the exhaust manifold (Fig. 11) or (Fig. 12).
Fig 13 Downstream Heated Oxygen Sensors
DOWNSTREAM OXYGEN SENSOR
The downstream heated oxygen sensor threads into the outlet pipe at the rear of the catalytic convertor (Fig. 13). The downstream heated oxygen
sensor input is used to detect catalytic convertor deterioration. As the convertor deteriorates, the input from the downstream sensor begins to match
the upstream sensor input except for a slight time delay. By comparing the downstream heated oxygen sensor input to the input from the upstream
sensor, the PCM calculates catalytic convertor efficiency.
