Subaru Legacy IV (2008 year). Manual - part 216

GD(H4SO)-166

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD

• Abnormality Judgement

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Time Needed for Diagnosis: 3000 s
Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

• Normality Judgement

Judge as OK and clear the NG if the continuous time while the following conditions are established is more
than the predetermined time.

Time Needed for Diagnosis: Less than 1 second

Judgement Value

Malfunction Criteria

Threshold Value

Fuel tank pressure

d –4 kPa (–30 mmHg, 
–1.2 inHg)

Judgement Value

Malfunction Criteria

Threshold Value

Fuel tank pressure

> –4 kPa (–30 mmHg, 
–1.2 inHg)

Cumulative time when all the malfunction 
criteria below are met.

t 30000 s

Purge control solenoid valve duty

Not = 0

Fuel temperature

–10 °C (14 °F) — 70 °C 
(158 °F)

Intake manifold relative pressure

t –26.7 kPa (–200 mmHg, 
–7.9 inHg)

GD(H4SO)-167

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

CO:DTC P1491 POSITIVE CRANKCASE VENTILATION (BLOW-BY) FUNCTION 

PROBLEM

1. OUTLINE OF DIAGNOSIS

Detect the blow-by hose release abnormality.
Judge as NG when the diagnosis terminal voltage is high.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Always perform the diagnosis continuously.

(1)

Engine control module (ECM)

(3)

PCV diagnosis connector

(4)

5 V

(2)

Detecting 

circuit

  

  

Secondary Parameters

Enable Conditions

None

EN-01790

E

(1)

(2)

(3)

(4)

GD(H4SO)-168

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD

• Abnormality Judgement

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Time Needed for Diagnosis: 2500 ms
Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

• Normality Judgement

Judge as OK and clear the NG if the continuous time while the following conditions are established is more
than the predetermined time.

Time Needed for Diagnosis: Less than 1 second

Judgement Value

Malfunction Criteria

Threshold Value

Battery voltage

t 10.9 V

Engine condition

After engine starting

Positive crankcase ventilation diagnosis 
voltage

High

Judgement Value

Malfunction Criteria

Threshold Value

Battery voltage

t 10.9 V

Engine condition

After engine starting

Positive crankcase ventilation diagnosis 
voltage

Low

GD(H4SO)-169

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

CP:DTC P1492 EGR SOLENOID VALVE SIGNAL #1 CIRCUIT MALFUNCTION 

(LOW INPUT)

1. OUTLINE OF DIAGNOSIS

• Detects open or short circuit of EGR.
• Judge as NG when the ECM output level differs from the actual terminal level.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Perform diagnosis continuously during EGR operation.

(1)

Engine control module (ECM)

(3)

Detecting circuit

(5)

Battery voltage

(2)

Computer unit (CPU)

(4)

Switch circuit

(6)

Main relay

Secondary Parameters

Enable Conditions

Elapsed time after starting the engine

t 1 second

EGR valve target position

> 0 step

Battery voltage

t 10.9 V

EN-02051

(1)

(2)

(3)

(4)

(5)

(6)