Subaru 2009 IMPREZA Service Manual page 1603

Diagnostic Trouble Code (DTC) Detecting Criteria
5. DIAGNOSTIC METHOD
• Abnormality Judgement
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.
Judgement Value
Malfunction Criteria
Front oxygen (A/F) sensor impedance
Time Needed for Diagnosis: 10000 ms
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
• Normality Judgement
Judge as OK and clear the NG if the continuous time while the following conditions are established is more
than the predetermined time.
Judgement Value
Malfunction Criteria
Front oxygen (A/F) sensor impedance
Time Needed for Diagnosis: 10000 ms
Threshold Value
> 50
Threshold Value
50
GD(H4DOTC)-15
GENERAL DESCRIPTION