Subaru 2009 IMPREZA Service Manual page 822

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
4. GENERAL DRIVING CYCLE
Perform the diagnosis only once at a constant 70 km/h (43.5 MPH) or higher.
5. DIAGNOSTIC METHOD
After establishing the execution conditions, calculate the front oxygen (A/F) sensor lambda deviation cumu-
lative value per 32 milliseconds × 4 ( |(sglmd
tion cumulative value ( |(ro2sad
cumulative value ( |(sglmd
nostic value.
• Abnormality Judgement
If the duration of time while the following conditions are met is within the time indicated, judge as NG.
Judgement Value
Malfunction Criteria
|(ro2sad – ro2sad )| /
n n–1
Time Needed for Diagnosis: 30 — 55 seconds
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 within
the predetermined time.
Judgement Value
Malfunction Criteria
|(ro2sad – ro2sad )| /
n n–1
Time Needed for Diagnosis: 30 — 55 seconds
n
– ro2sad )|), and when the front oxygen (A/F) sensor lambda deviation
n n–1
– sglmd )|) becomes the predetermined value or more, calculate the diag-
n n–1
|(sglmd – sglmd )| > 15.5
n n–1
|(sglmd – sglmd )| 15.5
n n–1
GD(H4SO)-98
– sglmd )|) and rear oxygen sensor output voltage devia-
n–1
Threshold Value
Threshold Value