Diagnostic Method

When both combination valve electromagnetic valve and the reed valve are open failure, the failure appears as pulses in the secondary air delivery pipe pressure sensor output. Detect abnormality by capturing these pulses using the following method.

• Abnormality Judgment 

  Calculate Max./Min. value of the secondary air delivery pipe pressure sensor output voltage and the sum of the output voltage deviation for the given time. Compare the difference between Max. and Min. values with threshold value and also compare the sum value with the threshold value. If both values exceed the threshold value, count up NG counter and then judge as NG if the counter reaches the given times.

  Judgment Value 

  JUDGMENT VALUE REFERENCE CHART
  
  

  Malfunction Criteria	Threshold Value
  Pipe inner pressure difference between Max. and Min.	> 0.05 V
  Sum of the pipe inner pressure variation value every 4 ms	> 5V
  Barometric pressure variation value	< 26.7 kPa (200 mmHg, 7.9 inHg)

  Time Needed for Diagnosis:  2000 ms x 20 time(s)

  Malfunction Indicator Light Illumination:  Illuminates as soon as a malfunction occurs.

• Normality Judgment 

  Judge as OK and clear NG if neither exceeds the threshold value, or if either of the two exceeds the threshold value.

  Judgment Value 

  JUDGMENT VALUE REFERENCE CHART
  
  

  Malfunction Criteria	Threshold Value
  Pipe inner pressure difference between Max. and Min.	≤ 0.05 V
  Sum of the pipe inner pressure variation value every 4 ms	≤ 5 V

  Time Needed for Diagnosis:  2000 ms