Subaru 2006 Legacy, Manual

Page: 1300 / 4302

GD(H4SO U5)-74
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
AI: DTC P0140 O2 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK1
SENSOR2)
1. OUTLINE OF DIAGNOSIS
Detect abnormalities in the rear oxygen sensor output characteristics.
By referring to the intake air amount, engine coolant temperature, main feedback control, deceleration fuel
cut and other operating conditions, if the rear oxygen sensor voltage should be moving under these condi-
tions but is showing a low voltage, this is judged as a Low side NG. If the voltage is showing a high voltage,
it is judged as a High side NG.
When either Low side or High side is NG, judged as rear oxygen sensor property NG.
2. ENABLE CONDITION
3. GENERAL DRIVING CYCLE
Perform the diagnosis only once after engine warm-up.
4. DIAGNOSTIC METHOD
Abnormality Judgment
When one of the following conditions is established, judged as NG.
Time Needed for Diagnosis:
200 seconds
Malfunction Indicator Light Illumination:
Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
Normality Judgment
When the following conditions are established, judged as OK.
Secondary Parameters Enable Conditions
Engine coolant temperature
≥
75°C (167°F)
Target output voltage of rear oxygen sen-
sor
≥
0.6 V
Air intake amount 10 g (0.35 oz)/seconds
or more
Battery voltage > 10.9 V
Closed loop at the oxygen sensor In operation
Misfire detection every 200 rotations 5 times or more
Front oxygen (A/F) sensor compensation
coefficient Not in limit value
Deceleration fuel cut of 5 seconds or
more. Experienced
Judgment Value
Malfunction Criteria Threshold Value
Maximum output voltage low side diag-
nosis < 0.55 V
Minimum output voltage high side diag-
nosis > 0.25 V
Judgment Value
Malfunction Criteria Threshold Value
Maximum output voltage low side diag-
nosis
≥
0.55 V
Minimum output voltage high side diag-
nosis
≤
0.25 V
asieps_tobira.book 74 ページ ２００９年１０月２６日 月曜日 午前９時１６分