Subaru Legacy IV (2008 year). Manual - part 219

GD(H4SO)-178

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

DG:DTC P2096 POST CATALYST FUEL TRIM SYSTEM TOO LEAN (BANK 1)

1. OUTLINE OF DIAGNOSIS

Detect the malfunction of fuel system from the size of the sub feedback learning value.
Control the sub feedback learning and judge as NG when the learning value is in the lean zone.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Perform the diagnosis continuously when the vehicle is idling or running at a constant speed of 80 km/h (50
MPH) or more.

(A)

Electromotive force

(C)

Rich

(E)

Theoretical air fuel ratio

(B)

Air fuel ratio

(D)

Lean

(F)

Comparative voltage

(1)

Atmosphere

(2)

Exhaust gas

(3)

Electromotive force

Secondary Parameters

Enable Conditions

Conditions for carrying out the sub feed-
back learning

Completed

Continuous time when all conditions are 
established.

t 1 s

EN-01696

(3)

V

(1)

(2)

(2)

(E)

(F)

(C)

(B)

(D)

(A)

GD(H4SO)-179

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: 5 s × 1 time(s)
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: 5 s

Judgement Value

Malfunction Criteria

Threshold Value

Sub feedback learning value

< –0.04 

Judgement Value

Malfunction Criteria

Threshold Value

Sub feedback learning value

t –0.04  + 0 

GD(H4SO)-180

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

DH:DTC P2097 POST CATALYST FUEL TRIM SYSTEM TOO RICH (BANK 1)

1. OUTLINE OF DIAGNOSIS

Detect the malfunction of fuel system from the size of the sub feedback learning value.
Sub feedback learning is being performed. When the learning value goes to the rich side, judge as NG.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Perform the diagnosis continuously when the vehicle is idling or running at a constant speed of 80 km/h (50
MPH) or more.

(A)

Electromotive force

(C)

Rich

(E)

Theoretical air fuel ratio

(B)

Air fuel ratio

(D)

Lean

(F)

Comparative voltage

(1)

Atmosphere

(2)

Exhaust gas

(3)

Electromotive force

Secondary Parameters

Enable Conditions

Conditions for carrying out the sub feed-
back learning

Completed

Continuous time when all conditions are 
established.

t 1 s

EN-01696

(3)

V

(1)

(2)

(2)

(E)

(F)

(C)

(B)

(D)

(A)

GD(H4SO)-181

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: 5 s × 1 time(s)
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: 5 s

Judgement Value

Malfunction Criteria

Threshold Value

Sub feedback learning value

t 0.03  (U5 model)
t 0.04
(Other than U5 model)

Judgement Value

Malfunction Criteria

Threshold Value

Sub feedback learning value

< 0.03  + –0.002  
(U5 model)
< 0.04  + –0.002  
(Other than U5 model)