MDX V6-3471cc 3.5L (2002)
Oxygen Sensor: Description and Operation
Primary Heated Oxygen Sensor (Primary HO2S)
The primary HO2S detects the oxygen content in the exhaust gas and sends signals to the PCM which varies the duration of fuel injection accordingly.
To stabilize its output, the sensor has an internal heater. The primary HO2S is installed in the exhaust manifold. By controlling the air fuel ratio with
primary HO2S and secondary HO2S, the deterioration of the primary HO2S can be evaluated by its feedback period. When the feedback period exceeds
a certain value during stable driving conditions, the sensor is considered deteriorated and the PCM sets a DTC.
Secondary Heated Oxygen sensor (Secondary HO2S)
The secondary HO2S detects the oxygen content in the exhaust gas in the downstream of the Three Way Catalytic Converter (TWC) and sends signals to
the PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The secondary HO2S is
installed in the TWC.
