Subaru 2006 Legacy, Manual

Page: 2924 / 4302

GD(H6DO)-126
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
0.04-inch Diagnosis
Mode Mode Description Diagnosis Period
Mode Z
(Purge control solenoid valve open-
ing failure diagnosis)
Perform purge control solenoid valve opening failure diagnosis
from the size of tank pressure variation from diagnosis start.
3 — 16 sec.
Mode A
(Estimated evaporation amount)
Calculate the tank pressure change amount (P1). 10 seconds
Mode B
(Sealed negative pressure, large
leakage judgment)
Decrease the pressure in the tank to the target value by introduc-
ing intake manifold pressure to the fuel tank.
If the tank pressure cannot be reduced, it is diagnosed as large
leak.
5 — 25 sec.
Mode C
(Pressure increase check,
advanced OK judgment)
Wait until the tank pressure returns to the targeted pressure (start
level of P2 calculation). If the tank pressure does not become the
value, make advanced OK judgment.
1 — 15 sec.
Mode D
(Negative pressure variation mea-
surement, evaporation leakage
diagnosis)
Calculate the tank pressure variation (P2), and obtain the diag-
nostic value using P1 found in Mode A.
Perform the evaporation diagnosis using the diagnostic value.
10 seconds
Mode Table for Evaporative Emission Control System Diagnosis
Mode When normal Diagnostic item DTC
Mode Z
Roughly same as atmospheric pressure
(Same pressure 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.
— —
Mode B
Negative pressure is formed due to
intake manifold negative pressure Large leak
P0457
Mode C Reaches target pressure — —
Mode D Pressure change is small.
EVAP system large leak [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
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