Subaru 2009 IMPREZA Service Manual page 764

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
5. DIAGNOSTIC METHOD
• Abnormality Judgement
Judge as NG if the criteria below are met.
Judgement Value
Malfunction Criteria
Engine coolant temperature
Timer for diagnosis after engine start
Timer for diagnosis after engine start
a. Timer stop at fuel cut
b. During the driving conditions except a) above, timer counts up as follows.
64 milliseconds + TWCNT milliseconds (at the time of 64 milliseconds)
TWCNT is defined as follows
TWCNT = 0 at idle switch ON
TWCNT show on the following table at idle switch OFF.
–20 (–4)
–10 (14)
Temperature
0 (32)
°C (°F)
10 (50)
20 (68)
Judgement value of timer after engine starting
t = 573669 ms – 33924 ms × Ti
Ti : The lowest coolant temperature after engine start
Time Needed for Diagnosis: Less than 1 second
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
• Normality Judgement
Judge as OK and clear the NG when the malfunction criteria below are met.
Judgement Value
Malfunction Criteria
Engine coolant temperature
Time Needed for Diagnosis: Less than 1 second
Threshold Value
< 20 °C (68 °F)
Judgement value of
timer after engine start
0 (0) 8 (5) 16 (9.9)
0 ms 32.076 ms 39.977 ms 47.879 ms 82.544 ms 117.209 ms 154.214 ms
0 ms 25.704 ms 33.606 ms 41.508 ms
0 ms 17.646 ms 25.548 ms
0 ms 7.901 ms 15.802 ms 23.704 ms 37.941 ms
0 ms 7.901 ms 15.802 ms 23.704 ms 37.941 ms
Threshold Value
20 °C (68 °F)
GD(H4SO)-40
Vehicle speed km/h (MPH)
24 (14.9) 32 (19.9) 40 (24.9)
68.52 ms 95.532 ms
33.45 ms 53.652 ms 73.855 ms
52.177 ms
52.177 ms
48 (29.8) 56 (34.8)
185.26 ms
125.667 ms 155.802 ms
97.12 ms 120.386 ms
68.573 ms 82.538 ms
68.573 ms 82.538 ms