Diagnostic Method
After the enable conditions have been established, calculate the front oxygen (A/F) sensor lambda deviation sum value and the rear oxygen sensor output voltage deviation sum value in every 32 ms x 4 times. If the front oxygen (A/F) sensor lambda deviation sum value is the predetermined value or more, calculate the diagnostic value.
If the duration of time while the following conditions are met is within the time indicated, judge as NG.
| Malfunction Criteria | Threshold Value |
|---|---|
| Catalyst monitor value - Rear oxygen sensor response compensation coefficient | < 0.35g (0.01oz) |
Catalyst monitor value* = | ( ((Intake air amount/14.7 - Intake air amount/main feedback λ value x 14.7) x 14.7 x 0.23) TF)|
* Catalyst monitor value will be calculated until the rear oxygen sensor exceeds 0.2 V after returning from fuel cut of 5 to 15 seconds.
Map TF = Temperature factor
| Estimated catalyst temperature °C (°F) | 450 (842) | 500 (932) | 600 (111 2) | 650 (120 2) | 700 (129 2) | 800 (147 2) | 900 (165 2) | 1000 (183 2) |
|---|---|---|---|---|---|---|---|---|
| Temperature factor | 1.15 | 1.1 | 1 | 1.15 | 1.2 | 1.2 | 1.2 | 1.2 |
Time needed for diagnosis: Less than 1 second
Malfunction indicator light illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.