Subaru 2009 IMPREZA Service Manual page 1766

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
CR:DTC P1418 SECONDARY AIR INJECTION SYSTEM CONTROL "A" CIRCUIT
SHORTED
1. OUTLINE OF DIAGNOSIS
Judge as NG when the ECM output level differs from the actual terminal level.
2. ENABLE CONDITIONS
Secondary Parameters
None
3. GENERAL DRIVING CYCLE
Always perform the diagnosis continuously.
4. DIAGNOSTIC METHOD
• 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
Battery voltage
Ignition
Terminal output voltage when ECM out-
puts ON signal
Time Needed for Diagnosis: 2500 ms
Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.
• 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
Battery voltage
Ignition
Terminal output voltage when ECM out-
puts ON signal
Time Needed for Diagnosis: Less than 1 second
Enable Condition
Threshold Value
10.9 V
ON
HIGH
Threshold Value
10.9 V
ON
LOW
GD(H4DOTC)-178