DTC Set Conditions

Check conditions are when engine coolant temperature is greater than 140°F (60°C), engine speed is 1500-3000 RPM (M/T) or 1200-3000 RPM (A/T), volumetric efficiency is 21-60 percent (M/T) or 30-60 percent (A/T), vehicle is under closed loop air/fuel control, the throttle valve is open, short-term fuel trim is more than -25 and less than 25 percent and more than 2 seconds have elapsed after the above mentioned conditions have been met. Monitoring time is 10 seconds by 7 times. Judgment criteria is when the heated oxygen sensor (front) sends "lean" and "rich" signals alternately 3 times or less for 10 seconds.

If the sensor switch time is longer than the judgment criteria due to the MUT-II OBD-II test Mode - H02S Test Results, it is assumed that the heated oxygen sensor has deteriorated. If it is short, it is assumed that the harness is damaged or has a short circuit. If the heated oxygen sensor signal voltage has not changed even once (lean/rich) after the DTC was erased, the sensor switch time will display as zero seconds.