Detection Condition

PCM compares number of front Heated Oxygen Sensor (HO2S) and rear HO2S inversions for a predetermined time. PCM monitors number of inversions rear side performs while front side inverts for a specified number of times when following monitoring conditions are met:

Monitoring Conditions

• Vehicle speed is 25-60 MPH.
• Calculated load is 19.5-44 percent.
• Engine speed is 1340-2000 RPM.

PCM detects inversion ratio. DTC is set, if inversion ratio is below threshold. This is an intermittent monitor. MIL is illuminated if PCM detects malfunction in 2 consecutive drive cycles.