Subaru Legacy IV (2008 year). Manual - part 612

GD(H6DO)-68

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

• Abnormality Judgement

1) Judge as NG when the judgment value is larger than the threshold value after deceleration fuel cut.
Response time (diagnosis value) > threshold value

o abnormal

2) If the oxygen sensor voltage is small after recovering from a deceleration fuel cut, and remains small,
judge as NG.

Time Needed for Diagnosis: 1 time(s)
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.

• Normality Judgement

1) Regardless of a deceleration fuel cut, if the response time (diagnosis value) when the oxygen sensor volt-
age has changed from rich to lean is shorter than the threshold value (judgment value), judge as a normal
condition.
Response time (diagnosis value)

d threshold value o normal

2) Do not judge as a normal condition.

Judge as OK and clear the NG if the following conditions are established.

Time Needed for Diagnosis: 1 time(s)

Judgement Value

Malfunction Criteria

Threshold Value

Shortest time change from lean (0.3 V
O

output) to rich (0.5 V) when voltage

changes from 0.25 V to 0.55 V

> 2000 ms

Longest time under 0.25 V

t 120000 ms

Judgement Value

Malfunction criteria

Threshold value

Shortest time change from lean (0.3 V
O

output) to rich (0.5 V) when voltage

changes from 0.25 V to 0.55 V

d 2000 ms

GD(H6DO)-69

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AR:DTC P0140 O2 SENSOR CIRCUIT NO ACTIVITY DETECTED

(BANK1 SENSOR2)

1. OUTLINE OF DIAGNOSIS

Detect the rear oxygen sensor open or short circuit. Judge as NG when the rear oxygen sensor voltage can
be determined to be abnormal considering conditions such as intake air amount, engine coolant tempera-
ture, main feedback control and deceleration fuel cut.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITION (USED ONLY FOR MALFUNCTION JUDGMENT)

4. GENERAL DRIVING CYCLE

Perform the diagnosis once after starting the engine.

(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

Closed loop control at the rear oxygen
sensor

In operation

Target output voltage of rear oxygen sen-
sor

t 0.55 V + 0.05 V

Amount of intake air

t 10 g/s (0.35 oz/s)

Engine coolant temperature

t 75 °C (167 °F)

Misfire detection every 200 rotations

< 7 time(s)

Front oxygen (A/F) sensor compensation
coefficient

Not in limit value

Battery voltage

t 10.9 V

Deceleration fuel cut of 5000 ms or
more.

Experienced

EN-01696

(3)

(1)

(2)

(E)

(F)

(C)

(B)

(D)

(A)

GD(H6DO)-70

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: 200000 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 following conditions are established.

Judgement Value

Malfunction Criteria

Threshold Value

Minimum output voltage

> 0.15 V

Maximum output voltage

< 0.55 V

Judgement Value

Malfunction Criteria

Threshold Value

Diagnosis of the rear oxygen sensor volt-
age low side

Incomplete

Minimum output voltage

d 0.15 V

Maximum output voltage

t 0.55 V

GD(H6DO)-71

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AS:DTC P0151 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 2 SENSOR 1)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0131. <Ref. to GD(H6DO)-51, DTC P0131 O2 SENSOR CIRCUIT
LOW VOLTAGE (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AT:DTC P0152 O2 SENSOR CIRCUIT HIGH VOLTAGE (BANK 2 SENSOR 1)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0132. <Ref. to GD(H6DO)-53, DTC P0132 O2 SENSOR CIRCUIT
HIGH VOLTAGE (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AU:DTC P0153 O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 1)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0133. <Ref. to GD(H6DO)-55, DTC P0133 O2 SENSOR CIRCUIT
SLOW RESPONSE (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AV:DTC P0154 O2 SENSOR CIRCUIT NO ACTIVITY DETECTED

(BANK 2 SENSOR 1)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0134. <Ref. to GD(H6DO)-58, DTC P0134 O2 SENSOR CIRCUIT
NO ACTIVITY DETECTED (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AW:DTC P0157 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 2 SENSOR 2)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0137. <Ref. to GD(H6DO)-60, DTC P0137 O2 SENSOR CIRCUIT
LOW VOLTAGE (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AX:DTC P0158 O2 SENSOR CIRCUIT HIGH VOLTAGE (BANK 2 SENSOR 2)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0137. <Ref. to GD(H6DO)-60, DTC P0137 O2 SENSOR CIRCUIT
LOW VOLTAGE (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AY:DTC P0159 O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 2)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0139. <Ref. to GD(H6DO)-64, DTC P0139 O2 SENSOR CIRCUIT
SLOW RESPONSE (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

AZ:DTC P0160 O2 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK2

SENSOR2)

1. OUTLINE OF DIAGNOSIS

NOTE:
For the detection standard, refer to DTC P0140. <Ref. to GD(H6DO)-69, DTC P0140 O2 SENSOR CIRCUIT
NO ACTIVITY DETECTED (BANK1 SENSOR2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

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