Diagnostic Method

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

• Abnormality Judgment 

  If the duration of time while the following conditions are met is within the time indicated, judge as NG.

  Judgment Value 

  MALFUNCTION CRITERIA AND THRESHOLD VALUE REFERENCE
  
  

  Malfunction criteria	Threshold value
  Σ |(ro2sadn - ro2sadn-1 )| / Σ |(sglmdn - sglmdnn-1 )|	> 25

  Time Needed for Diagnosis:  30 - 55 seconds

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

• Normality Judgment 

  Judge as OK and clear the NG if the continuous time while the following conditions are established is within the predetermined time.

  Judgment Value 

  MALFUNCTION CRITERIA AND THRESHOLD VALUE REFERENCE
  
  

  Malfunction criteria	Threshold value
  Σ |(ro2sadn - ro2sadn-1 )| / Σ |(sglmdn - sglmdn-1 )|	< 25

  Time Needed for Diagnosis:  30 - 55 seconds