Function Explanation (DTC Detection Outline)

• If the fuel amount^*1 supplied to the catalyst, from the period of recovery by fuel cut control until the HO2S indicates a rich signal (0.2 V or more  ), is less than the specified value, the PCM determines catalytic converter deterioration and stores a DTC.

^*1 : The estimated value is calculated based on the A/F sensor signal.

Fig 1: A/F Sensor Signal And HO2S Signal Waveform

Courtesy of MAZDA MOTORS CORP.