Subaru Legacy IV (2008 year). Manual - part 623

GD(H6DO)-112

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

Valve Operation and Air Flow

In the figure below, divided by the diaphragm, the part above X is charged with atmospheric air pressure, and
the part below X is charged with tank pressure. Also, the part above Y is charged with tank pressure, and the
part below Y is charged with canister pressure.
If the atmospheric air pressure port is A, tank pressure port is B, and canister pressure port is C, the air flows
according to pressure difference from each port as shown in the table below.

When A < B (solenoid OFF)

(a)

Barometric pressure

(b)

Fuel tank

(c)

Canister

Condition of pressure

Flow

A < B (solenoid OFF)

o C

B < C (solenoid OFF)

o B

Solenoid ON

m o C

(a)

Barometric pressure

(b)

Fuel tank

(c)

Canister

EN-01716

(a)

(b)

(c)

EN-01717

(a)

(b)

(c)

GD(H6DO)-113

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

When B < C (solenoid OFF)

When Solenoid is ON

(a)

Barometric pressure

(b)

Fuel tank

(c)

Canister

(1)

Valve

(a)

Barometric pressure

(b)

Fuel tank

(c)

Canister

EN-01718

(a)

(b)

(c)

(1)

EN-01719

(a)

(b)

(c)

GD(H6DO)-114

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

Drain valve

Drain valve controls the ambient air to be introduced to the canister.

3. ENABLE CONDITION

0.04-inch Diagnosis

Secondary Parameters

Enable Conditions

Battery voltage

t 10.9 V

Barometric pressure

t 75 kPa (563 mmHg, 22.2 inHg)

Total time of canister purge operation

t 120000 ms

Elapsed time after starting the engine

t 856 s

Learning value of evaporation gas density

< 0.08

Engine speed

1050 rpm — 6500 rpm

Fuel tank pressure

t –4 kPa (–30 mmHg, –1.2 inHg)

Intake manifold relative vacuum (relative pressure)

t – 26.7 kPa (– 200 mmHg, – 7.9 inHg)

Vehicle speed

t 32 km/h (19.9 MPH)

Fuel level

9.6

2 (2.54 US gal, 2.11 Imp gal) — 54.4 2 (14.37 US gal,

11.97 Imp gal)

Closed air/fuel ratio control

In operation

Fuel temperature

–10 °C (14 °F) — 45 °C (113 °F)

Intake air temperature

t –10 °C (14 °F)

Pressure change every one second

< 1.7 mmHg (Mode A)

< 1.7 mmHg (Mode D)

Minimum pressure change value every one sec-
ond – Maximum pressure change value every
one second

< 1.7 mmHg (Mode A)

< 1.7 mmHg (Mode D)

Change of fuel level per 128 milliseconds

< 2

2 (0.53 US gal, 0.44 Imp gal)

Air fuel ratio

0.76 — 1.25

EN-02293

GD(H6DO)-115

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

0.02-inch Diagnosis

4. GENERAL DRIVING CYCLE

0.04-inch Diagnosis

• Perform the diagnosis only once in 856 seconds or more after starting the engine, at a constant speed of
32 km/h (20 MPH) or more.
• Pay attention to the fuel temperature and fuel level.

0.02-inch Diagnosis

• Perform the diagnosis 125 seconds or more at a constant engine speed of 50 km/h (31 MPH) or higher to
judge as NG or OK.
• If judgement cannot be made, repeat the diagnosis.
• Pay attention to the fuel level.

Secondary Parameters

Enable Conditions

At starting a diagnosis

Evap. diagnosis

Incomplete

Battery voltage

t 10.9 V

Barometric pressure

t 75 kPa (563 mmHg, 22.2 inHg)

Time since last incomplete 0.02-inch leakage
diagnosis

When cancelling in mode A

> 120000 ms

When cancelling in other than mode A

> 600000 ms

Total time of canister purge operation

t 120000 ms

Elapsed time after starting the engine

t 120 s

Fuel temperature

–10 °C (14 °F) — 55 °C (131 °F)

Fuel level

9.6

2 (2.54 US gal, 2.11 Imp gal) — 54.4 2 (14.37 US gal,

11.97 Imp gal)

Intake manifold relative vacuum (relative pressure)

t – 8 kPa (– 60 mmHg, – 2.4 inHg)

Fuel tank pressure

–0.7 kPa (–5 mmHg, –0.2 inHg) — 1.4 kPa (10.7 mmHg,
0.4 inHg)

Vehicle speed

50 km/h (31.1 MPH) — 510 km/h (316.9 MPH) continues
for 125000 ms

Closed air/fuel ratio control

In operation

Engine speed

1050 rpm — 7000 rpm

During diagnosis

Change of fuel level

d Value of Map 4

Pressure change every one second

< 0.1 kPa (0.44 mmHg, 0 inHg)

Minimum pressure change value every one sec-
ond – Maximum pressure change value every
one second

< 0.1 kPa (0.51 mmHg, 0 inHg) (Mode D)

| Pressure change in tank every second |

d 0.1 kPa (0.75 mmHg, 0 inHg)

Barometric pressure change

–0.5 kPa (–3.6 mmHg, –0.1 inHg) — 0.3 kPa (2.4 mmHg,
0.1 inHg) (Mode D)

–0.3 kPa (–2.4 mmHg, –0.1 inHg) — 0.3 kPa (2.4 mmHg,
0.1 inHg) (Mode E)

Map4

Fuel level (

2, US gal, Imp gal)

10, 2.64,

2.2

20, 5.28,

4.4

30, 7.93,

6.6

40, 10.57,

8.8

50, 13.21,

60, 15.85,

13.2

Change (

2, US gal, Imp gal)

5, 1.32, 1.1

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