Subaru 2009 IMPREZA, Service Manual

Page: 824 / 3619

GD(H4SO)-100
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
0.04-inch Diagnosis
Mode Table for Evaporative Emission Control System Diagnosis
Mode Mode Description Diagnosis Period
Mode Z
(Purge control solenoid valve
opening failure diagnosis)
Perform purge control solenoid valve opening failure diagnosis from
the size of tank pressure variation from diagnosis start.
0 ms + 3000 ms —
0 ms + 3000 ms +
13000 ms
Mode A
(Estimated evaporation amount)
Calculate the tank pressure change amount (P1). 10000 ms
Mode B
(Sealed negative pressure, large
leakage judgement)
Decrease the pressure in the tank to the target value by introducing
the intake manifold pressure to the fuel tank.
If the tank pressure cannot be reduced, it is diagnosed as large leak.
0 — 10000 ms +
25000 ms
Mode C
(Pressure increase check,
advanced OK judgement)
Wait until the tank pressure returns to the target (start level of P2 cal-
culation). If the tank pressure does not become the value, make
advanced OK judgement.
0 — 18600 ms
Mode D
(Negative pressure variation measure-
ment, evaporation leakage diagnosis)
Calculate the tank pressure variation (P2), and obtain the diagnostic
value using P1 found in Mode A.
Perform the evaporation diagnosis using the diagnostic value.
0 ms + 10000 ms
Mode
Behavior of tank internal pressure under
normal conditions
Diagnostic item DTC
Mode Z
Roughly the same as barometric pres-
sure (Same as 0 kPa (0 mmHg, 0 inHg)) Purge control solenoid valve is judged to
be open.
P0457
Mode A
Pressure is in proportion to amount of
evaporative emission.
— None
Mode B
Negative pressure is formed due to
intake manifold negative pressure
Large leak P0457
Mode C Reaches target pressure — None
Mode D Pressure change is small.
EVAP system large leak determination.
[1.0 mm (0.04 in)]
P0442
Mode
Z
Mode
A
Mode
B
Mode
C
Mode
D
OK OK OK OK OK
NG
Early OK
Large leakage judgement
Cancel
Mode
Z
Extend
NG
NG
OK
END
EN-02872