Monitor Description
The ECM uses diagnostic values to determine deterioration of the catalyst. If the diagnostic value exceeds a specified value, the catalyst is considered deteriorated, and the DTC is stored.
The diagnostic values are based upon the catalyst monitor value (CM) calculated by changes in the air fuel ratio sensor lambda and changes in the heated oxygen sensor output voltage, and in the response rate calculated from the heated oxygen sensor response time.
*: Diagnostic Value = CM X (1 + Response rate)