Subaru Legacy IV (2008 year). Manual - part 624

 

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Subaru Legacy IV (2008 year). Manual - part 624

 

 

GD(H6DO)-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 judgment cannot be made, extend Mode Z, and Judge as NG when the following conditions are estab-
lished 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 judgment for purge control solenoid valve stuck open NG is made, end the evaporative diagnosis.
Cancel the evaporative diagnosis when the OK/NG judgment 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(H6DO)-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 judgment

(2)

3000 ms

(4)

0.4 kPa (3 mmHg, 0.1 inHg)

 

 

EN-02869

(1)

(2)

(4)

evptez

evptezini

evptezha

0

(3)

(5)

GD(H6DO)-118

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

Purge control solenoid valve Open Fixation

• evptezini 

d 1.4 kPa (10.7 mmHg, 0.4 inHg)

• evptez – evptezha > 0.6 kPa (4.5 mmHg, 0.2 inHg)
• No fuel sloshing of over 2 

2 (0.53 US gal, 0.44 Imp gal) lasts for more than 40000 ms.

Judge as abnormal when all are established.

(1)

Mode Z

(4)

Fuel tank pressure

(7)

40000 ms no fuel sloshing

(2)

Extended mode Z

(5)

0.6 kPa (4.5 mmHg, 0.2 inHg)

(8)

NG judgment

(3)

3000 ms + 13000 ms

(6)

1.4 kPa (10.7 mmHg, 0.4 inHg)

 

 

EN-02870

(8)

(7)

(6)

(4)

(5)

evptez

evptezini

evptezha

0

(3)

(2)

(1)

GD(H6DO)-119

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

Leak Diagnosis

DTC
P0442 Evaporative Emission Control System Leak Detected (Small Leak)
P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)
• The diagnostic consists of creating a sealed vacuum in the fuel tank and then determining the presence of
leakage from the speed at which the tank internal pressure returns to barometric pressure.
• The diagnosis is divided into the following five phases.
Mode A: (Estimated evaporation gas amount)
Calculate the tank pressure change amount (P1) when using mode A. After calculating P1, switch to mode B.
Mode B: (Negative pressure sealed)
Introduce negative pressure in the intake manifold to the tank.
Approx. 0 

o –1.4 kPa (0 o –10.5 mmHg, 0 o –0.4 inHg)

When the pressure above (desired negative pressure) is reached, enters Mode C.
In this case, if the tank pressure does not reach the target negative pressure, judge that there is a large leak-
age in the system and terminate the evaporative emission control system diagnosis.
Abnormality Judgement
Judge as NG (large leakage) when the following conditions are established.

Time Needed for Diagnosis: 0 ms + 3000 ms + 10000 ms + 10000 ms + 25000 ms
Mode C: (Check pressure rise)
Stop the introduction of negative pressure. (Wait until the tank pressure returns to the start level of P2 cal-
culation.)
Change to Mode D when the tank pressure returns to the start level of P2 calculation.
Judge immediate OK and change to Mode E when it does not return in spite of spending the specified time.

Time Needed for Diagnosis: 0 ms + 3000 ms + 10000 ms + 10000 ms + 25000 ms + 17000 ms

Judgement Value

Malfunction criteria

Threshold value

DTC

Time to reach target negative pressure

t 10000 ms + 25000 ms P0457

or

  

Mode B time

t 10000 ms

 

(Min. pressure value in tank when in 
mode B) – (Tank pressure when mode B 
started)

> –0.3 kPa (–2.5 mmHg, 
–0.1 inHg)

Tank pressure when starting cal-

culation of P2

Time for advanced OK 

judgment

–1.3 kPa (–9.75 mmHg, –0.4 inHg) 17000 ms

 

 

 

 

 

 

 

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