Subaru Legacy IV (2008 year). Service manual — part 421

GD(H4DOTC)-134

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

BT:DTC P0458 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE

CIRCUIT LOW

1. OUTLINE OF DIAGNOSIS

Detect open or short circuit of the purge control solenoid valve.
Judge as NG when the ECM output level differs from the actual terminal level.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Always perform the diagnosis after starting the engine.

(A)

To canister

(B)

To intake manifold

Secondary Parameters

Enable Conditions

Battery voltage

t 10.9 V

Elapsed time after starting the engine

t 1 second

(A)

(B)

EN-02197

GD(H4DOTC)-135

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 when malfunction occurs in 2 continuous driving cy-
cles.

• 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

Duty ratio of “ON”

< 0.75

Terminal output voltage

Low

Judgement Value

Malfunction Criteria

Threshold Value

Terminal output voltage

High

GD(H4DOTC)-136

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

BU:DTC P0459 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE

CIRCUIT HIGH

1. OUTLINE OF DIAGNOSIS

Detect open or short circuit of the purge control solenoid valve.
Judge as NG when the ECM output level differs from the actual terminal level.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Always perform the diagnosis after starting the engine.

(A)

To canister

(B)

To intake manifold

Secondary Parameters

Enable Conditions

Battery voltage

t 10.9 V

Elapsed time after starting the engine

t 1 second

(A)

(B)

EN-02197

GD(H4DOTC)-137

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 when malfunction occurs in 2 continuous driving cy-
cles.

• 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

Duty ratio of “ON”

t 0.25

Terminal output voltage

High

Judgement Value

Malfunction Criteria

Threshold Value

Terminal output voltage

Low