Subaru 2009 IMPREZA Service Manual page 1812

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
EH:DTC P2420 EVAPORATIVE EMISSION SYSTEM SWITCHING VALVE CONTROL
CIRCUIT HIGH
1. OUTLINE OF DIAGNOSIS
Detect open or short circuit of the purge control solenoid valve 2.
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
Elapsed time after starting the engine
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
Elapsed time after starting the engine
Terminal output voltage when ECM out-
puts ON signal
Time Needed for Diagnosis: Less than 1 second
Enable Condition
Threshold Value
10.9 V
1 second
High
Threshold Value
10.9 V
1 second
Low
GD(H4DOTC)-224