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Subaru Legacy IV (2008 year). Manual - part 416

GD(H4DOTC)-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 – 13.3 kPa (– 100 mmHg, – 3.9 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 second –
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(H4DOTC)-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 diag-
nosis

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 – 13.3 kPa (– 100 mmHg, – 3.9 inHg)

Fuel tank pressure

–0.4 kPa (–3.2 mmHg, –0.1 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 — 6000 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 second –
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

GD(H4DOTC)-116

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD

Purge control solenoid valve stuck open fault diagnosis

DTC
P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)
Purpose of Mode Z
When performing the leakage diagnosis of EVAP system, the purge control solenoid valve must operate nor-
mally. Therefore, mode Z is used to diagnose the purge control solenoid valve stuck open condition. Note
that if a purge control solenoid valve stuck open fault is detected, the EVAP system leakage diagnosis is can-
celled.
Diagnostic method
Purge control solenoid valve functional diagnosis is performed by monitoring the tank pressure in mode Z.
• Abnormality Judgement
If OK judgement cannot be made, extend Mode Z, and Judge as NG when the following conditions are es-
tablished after predetermined amount of time.

Time Needed for Diagnosis: 0 ms + 3000 ms + 13000 ms
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
When judgement for purge control solenoid valve stuck open NG is made, end the evaporative diagnosis.
Cancel the evaporative diagnosis when the OK/NG judgement for purge control solenoid valve stuck open
cannot be made in Mode Z.
• Normality Judgement
Judge as OK and change to Mode A when the following conditions are established after predetermined time
has passed since Mode Z started.

Judgement Value

Malfunction Criteria

Threshold Value

DTC

evptez – evptezha

> 0.6 kPa (4.5 mmHg,
0.2 inHg)

P0457

evptezini

d 1.4 kPa (10.7 mmHg,
0.4 inHg)

Time of 2

2 (0.53 US gal, 0.44 Imp gal)

or more fuel no sloshing

t 40000 ms

Judgement Value

Malfunction Criteria

Threshold Value

DTC

evptez – evptezha

d 0.4 kPa (3 mmHg,
0.1 inHg)

P0457

GD(H4DOTC)-117

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

Normal

evptez – evptezha

d 0.4 kPa (3 mmHg, 0.1 inHg) Normal when above is established

Time Needed for Diagnosis: 0 ms + 3000 ms

(1)

Mode Z

(3)

Fuel tank pressure

(5)

OK judgement

(2)

3000 ms

(4)

0.4 kPa (3 mmHg, 0.1 inHg)

EN-02869

(1)

(2)

(4)

evptez

evptezini

evptezha

(3)

(5)

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