Subaru 2009 IMPREZA Service Manual page 1690

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
Combination valve both closed pulse diagnosis
Perform open stuck diagnosis of both combination valves using delivery pipe pressure pulse when both com-
bination valves are closed. Determine which side of valves is stuck open by comparing secondary air flow
amount when RH combination valve is closed with that when LH combination valve is closed.
Calculate voltage pulse of the pump supply pipe pressure when both combination valves are closed. The cal-
culation should be small because there is no pulse from supply pipe pressure with both combination valves
closed. When the calculation is large, determine that either of the combination valves is stuck open.
Determine which side of valves is stuck open by comparing secondary air flow amount when the RH combi-
nation valve is closed with that when the LH combination valve is closed. Air flow amount is larger on the
open stuck valve.
• 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
Pulse calculation value when both com-
bination valves are closed
Air flow amount when the right bank is
closed (value from Map 4)
Pulse calculation value when both com-
bination valves are closed
Air flow amount when the left bank is
closed (value from Map 5)
Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
• 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
Pulse calculation value when both com-
bination valves are closed
Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms
Threshold Value
> Value of Map 3 P2440
Air flow amount
when the left bank is
closed
(value from Map 5)
> Value of Map 3 P2442
> Air flow amount
when the right bank is
closed
(value from Map 4)
Threshold Value
Value of Map 3 P2440, P2442
GD(H4DOTC)-102
DTC
DTC