Accord SE Sedan L4-2254cc 2.3L SOHC (VTEC) MFI (2002)
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Oxygen Sensor: Description and Operation
Primary Heated Oxygen sensor (Primary HO(2)S)
The primary HO(2)S detects the oxygen content in the exhaust gas and sends signals to the ECM/PCM which varies the duration of fuel injection
accordingly. To stabilize its output, the sensor has an internal heater. The primary HO(2)S is installed in the exhaust manifold. By controlling the air fuel
ratio with primary HO(2)S and secondary HO(2)S, the deterioration of the primary HO(2)S 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 ECM/PCM sets a DTC.
Secondary Heated Oxygen sensor (Secondary HO(2)S)
The secondary HO(2)S detects the oxygen content in the exhaust gas downstream of the Three Way Catalytic Converter (TWC) and sends signals to the
ECM/PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The secondary HO(2)S is
installed in the TWC.
Air Fuel Ratio (A/F) Sensor (F23A4 engine)
The A/F Sensor operates over a wide air/fuel range. The A/F Sensor is installed in the exhaust manifold.
