Subaru 2009 IMPREZA Service Manual page 775

Diagnostic Trouble Code (DTC) Detecting Criteria
• 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
parafca = td2faf/td2lmd
where,
td2faf (N) = td2faf (n–1) + |d2faf (n)|
td2lmd (N) = td2lmd (n–1) + |d2lmd (n)|
add up to 32 ms × 4 × 1640 time(s).
d2faf (n) = (faf (n) – faf (n–1)) – (faf (n–1) – faf (n–2))
d2lmd (n) = (lmd (n) – lmd (n–1)) – (lmd (n–1) – lmd (n–2))
faf = main feedback compensation coefficient every
128 milliseconds
lmd = output lambda every 128 milliseconds
Time Needed for Diagnosis: 32 ms × 4 × 1640 time(s)
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
parafca = td2faf/td2lmd
where,
td2faf (N) = td2faf (n–1) + |d2faf (n)|
td2lmd (N) = td2lmd (n–1) + |d2lmd (n)|
add up to 32 ms × 4 × 1640 time(s).
d2faf (n) = (faf (n) – faf (n–1)) – (faf (n–1) – faf (n–2))
d2lmd (n) = (lmd (n) – lmd (n–1)) – (lmd (n–1) – lmd (n–2))
faf = main feedback compensation coefficient every
128 milliseconds
lmd = output lambda every 128 milliseconds
Time Needed for Diagnosis: 32 ms × 4 × 1640 time(s)
Threshold Value
> 0.45
Threshold Value
0.45
GD(H4SO)-51
GENERAL DESCRIPTION