DTC Set Conditions
- Check Conditions - Engine coolant temperature is higher than 140°F (60°C). Engine speed is between 1500-3000 RPM (M/T) or 1200-3000 RPM (A/T). Volumetric efficiency is between 21-60% (M/T) or 30-60% (A/T). Under the closed loop air/fuel control. The throttle valve is open. Short-term fuel trim is between -25% and +25%. More than 2 seconds have elapsed after the afore mentioned conditions have been met. The ECM (M/T) or PCM (A/T) monitors for this condition for 7 cycles of 10 seconds each during the drive cycle.
- Judgement Criteria - The heated oxygen sensor (front) sends "lean" and "rich" signals alternately 8 times or less for 10 seconds.
NOTE:
If the sensor switching frequency is lower than the Judgement Criteria due to the MUT-II OBD-II test Mode - HO2S Test Results, it is assumed that the heated oxygen sensor has deteriorated. If it is higher, 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 0 seconds.