Subaru IMPREZA GD 2007 Series Manual page 1863

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Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
Abnormality Judgment
1) Judge as NG when the judgment value is larger than the threshold value after deceleration fuel cut.
Response time (diagnosis value) > threshold value → abnormal
2) If the oxygen sensor voltage is small after recovering from a deceleration fuel cut, and remains small,
judge as NG.
Judgment Value
Malfunction Criteria
Shortest time change from lean (300 mV
O output) to rich (500 mV) when voltage
2
increases from 250 mV to 550 mV
Time at less than 150 mV
Time Needed for Diagnosis: 1 time
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in two continuous driving
cycles.
Normality Judgment
1) Regardless of a deceleration fuel cut, if the response time (diagnosis value) when the oxygen sensor volt-
age has changed from rich to lean is shorter than the threshold value (judgment value), judge as a normal
condition.
Response time (diagnosis value) ≤ threshold value → normal
2) Do not judge as a normal condition.
Judge as OK when the criteria below are met.
Judgment Value
Malfunction Criteria
Shortest time change from lean (300 mV
O output) to rich (500 mV) when voltage
2
increases from 250 mV to 550 mV
13.DTC CLEAR CONDITION
• When the OK idling cycle is completed 40 times in a row
• When "Clear Memory" is performed
14.MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
• When the OK driving cycle is completed three times in a row
• When "Clear Memory" is performed
15.FAIL SAFE
Sub feedback control: Not allowed
16.ECM OPERATION AT DTC SETTING
• Memorize the freeze frame data. (For test mode $02)
• Memorize the diagnostic value and trouble standard value. (For test mode $06)
Threshold Value
> 2 seconds
> 120 seconds
Threshold Value
≤ 2 seconds
GD(H4DOTC)-72