Diagnostic Method

After establishing the execution conditions, calculate the front oxygen (A/F) sensor lambda deviation cumulative value per 32 milliseconds X 4 (Σ |(sglmd_n - sglmd_n-1 )|) and rear oxygen sensor output voltage deviation cumulative value (Σ |(ro2sad_n - ro2sad_n-1 )|), and when the front oxygen (A/F) sensor lambda deviation cumulative value (Σ |(sglmd_n - sglmd_n-1 )|) becomes 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.

JUDGMENT VALUE

Malfunction Criteria	Threshold Value
Σ \|(ro2sad_n - ro2sad_{n - 1} )\|/Σ \|(sglmd_n - sglmd_{n - 1} )\| (bank 2)	> 7

Time Needed for Diagnosis: 30 - 55 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.