Signal Waveform & Data
The output voltage of front HO2S changes continuously according to air/fuel ratio. The ECM (PCM) controls fuel amount based on this value. Preheating is necessary for HO2S normal operation. A heater unit is installed in each HO2S. The ECM (PCM) can control air/fuel ratio with the output signal of HO2S simultaneous with engine run by reducing preheating time. The HO2S power source is the engine control relay. ECM (PCM) operates heater by ground control.