Detection Condition
WARNING: This page is about a different car, the 2003 Mazda MPV and 2002 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.
PCM monitors inversion cycle period, lean-to-rich and rich-to-lean response time. PCM calculates average response time during Drive Mode 3, when monitoring conditions are met.
Monitoring Conditions
- Calculation load: 26.6-57.8 percent depends on engine speed.
- Engine speed: 1500-2500 RPM.
- Engine coolant temperature is more than 14°F (-10°C).
If response time exceeds threshold, PCM determines HO2S circuit has malfunction. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction in 2 consecutive drive cycles.