
EN(H6DO)(diag)-347
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC)”.
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK FRONT OXYGEN (A/F) SENSOR DA-
TA.
1) Start the engine.
2) While observing the Subaru Select Monitor
or general scan tool screen, warm-up the
engine until engine coolant temperature is
above 75°C (167°F).
If the engine is already warmed-up, operate at
idle speed for at least 1 minute.
3) Read data of front oxygen (A/F) sensor sig-
nal using the Subaru Select Monitor or general
scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value within
0.86 — 1.15 at idle?
Go to step 3.Go to step 4.
3CHECK REAR OXYGEN SENSOR SIGNAL.
1) Race engine at speeds from idling to 5,000
rpm for a total of 5 cycles.
NOTE:To increase engine speed to 5,000 rpm, slowly
depress accelerator pedal, taking approximate-
ly 5 seconds, and quickly release accelerator
pedal to decrease engine speed.
2) Operate the LED operation mode for
engine.
NOTE:•Subaru Select Monitor
For detailed operation procedure, refer to the
“LED OPERATION MODE FOR ENGINE.”.
Does the LED of {Rear O2
Rich Signal} blink?
Check front oxy-
gen (A/F) sensor
circuit.
Check rear oxygen
sensor circuit.
Rear Oxygen Sen-
sor.>
4 CHECK EXHAUST SYSTEM.
Check exhaust system parts.
NOTE:Check the following items.
•Looseness of part installation
•Damage (crack, hole etc.) of parts
•Looseness of the front oxygen (A/F) sensor
•Looseness or ill fitting of parts between front
oxygen (A/F) sensor and rear oxygen sensor
Is there any fault in exhaust
system?
Repair or replace
faulty par ts.
Go to step 5.
5CHECK AIR INTAKE SYSTEM.Are there holes, loose bolts or
disconnection of hose on air
intake system?
Repair the air
intake system.
Go to step 6.

EN(H6DO)(diag)-355
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC)”.
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK FRONT OXYGEN (A/F) SENSOR DA-
TA.
1) Start the engine.
2) While observing the Subaru Select Monitor
or general scan tool screen, warm-up the
engine until engine coolant temperature is
above 75°C (167°F).
If the engine is already warmed-up, operate at
idle speed for at least 1 minute.
3) Read data of front oxygen (A/F) sensor sig-
nal using the Subaru Select Monitor or general
scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value within
0.86 — 1.15 at idle?
Go to step 3.Go to step 4.
3CHECK REAR OXYGEN SENSOR SIGNAL.
1) Race engine at speeds from idling to 5,000
rpm for a total of 5 cycles.
NOTE:To increase engine speed to 5,000 rpm, slowly
depress accelerator pedal, taking approximate-
ly 5 seconds, and quickly release accelerator
pedal to decrease engine speed.
2) Operate the LED operation mode for
engine.
NOTE:•Subaru Select Monitor
For detailed operation procedure, refer to the
“LED OPERATION MODE FOR ENGINE.”.
Does the LED of {Rear O2
Rich Signal} blink?
Check front oxy-
gen (A/F) sensor
circuit.
Check rear oxygen
sensor circuit.
Rear Oxygen Sen-
sor.>
4 CHECK EXHAUST SYSTEM.
Check exhaust system parts.
NOTE:Check the following items.
•Looseness of part installation
•Damage (crack, hole etc.) of parts
•Looseness of the front oxygen (A/F) sensor
•Looseness or ill fitting of parts between front
oxygen (A/F) sensor and rear oxygen sensor
Is there any fault in exhaust
system?
Repair or replace
faulty par ts.
Go to step 5.
5CHECK AIR INTAKE SYSTEM.Are there holes, loose bolts or
disconnection of hose on air
intake system?
Repair the air
intake system.
Go to step 6.

EN(H6DO)(diag)-390
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
EE:DTC P2227 BAROMETRIC PRESSURE CIRCUIT RANGE/PERFORMANCE
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
EF:DTC P2228 BAROMETRIC PRESSURE CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
•Immediately at fault recognition
•GENERAL DESCRIPTION
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Replace the ECM.
Engine Control
Module (ECM).>
NOTE:
The barometric
pressure sensor is
built into the ECM.
It is not necessary
to inspect DTC
P0129.
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is DTC P1110 displayed on the
Subaru Select Monitor or gen-
eral scan tool?
Replace the ECM.
Engine Control
Module (ECM).>
NOTE:The barometric
pressure sensor is
built into the ECM.
Te m p o r a r y p o o r
contact occurs.

EN(H6DO)(diag)-391
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
EG:DTC P2229 BAROMETRIC PRESSURE CIRCUIT HIGH INPUT
DTC DETECTING CONDITION:
•Immediately at fault recognition
•GENERAL DESCRIPTION
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is DTC P1111 displayed on the
Subaru Select Monitor or gen-
eral scan tool?
Replace the ECM.
Engine Control
Module (ECM).>
NOTE:
The barometric
pressure sensor is
built into the ECM.
Te m p o r a r y p o o r
contact occurs.

GD(H6DO)-14
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
4. GENERAL DRIVING CYCLE
Perform the diagnosis continuously 6 seconds after engine start while variable valve lift is being controlled.
5. DIAGNOSTIC METHOD
Abnormality Judgment
Judge as NG when the continuous time is longer than the predetermined time when the following conditions
are established.
Time Needed for Diagnosis:
Low side 0.784 seconds
High side: 3.0 seconds
Malfunction Indicator Light: Illuminates as soon as a malfunction occurs.
Normality Judgment
When the continuous time is more than 3 seconds while the following conditions are established, judge as
OK and clear the NG.
6. DTC CLEAR CONDITION
•When the OK idling cycle is completed 40 times in a row
•When “Clear Memory” is performed
7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
•When the OK driving cycle is completed 3 times in a row
•When “Clear Memory” is performed
8. FAIL SAFE
None
9. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)
Judgment Value
Malfunction Criteria Threshold Value
Low NG
Duty ratio≥ 62%
Va r i a b l e va l v e l i f t d i a g n o s i s o i l p r e s s u r e
switch
OFF
High NG
Duty ratio < 33%
Va r i a b l e va l v e l i f t d i a g n o s i s o i l p r e s s u r e
switch
ON
Judgment Value
Malfunction Criteria Threshold Value
Low OK
Duty ratio≥ 62%
Va r i a b l e va l v e l i f t d i a g n o s i s o i l p r e s s u r e
switch
ON
High OK
Duty ratio < 33%
Va r i a b l e va l v e l i f t d i a g n o s i s o i l p r e s s u r e
switch
OFF

GD(H6DO)-16
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
5. DIAGNOSTIC METHOD
Judge as NG when the continuous time of meeting the malfunction criteria below becomes more than the
time needed for diagnosis (10 seconds). Judge as OK and clear NG when the continuous time of not com-
pleting the malfunction criteria below becomes more than the time needed for diagnosis (10 seconds).
Time Needed for Diagnosis: 10 seconds
Malfunction Indicator Light Illumination: Illuminates when malfunctions occur in 2 continuous driving cy-
cles.
6. DTC CLEAR CONDITION
•When the OK idling cycle is completed 40 times in a row
•When “Clear Memory” is performed
7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
•When the OK driving cycle is completed 3 times in a row
•When “Clear Memory” is performed
8. FAIL SAFE
•Front oxygen (A/F) sensor main learning compensation: Not allowed to calculate.
•Rear oxygen sensor sub learning compensation: Not allowed to calculate.
•Purge control: Not allowed to purge
9. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)
Judgment Value
Malfunction Criteria Threshold Value
Fr o nt ox yg e n ( A / F) s en so r im pe d an c e > 5 0 Ω

GD(H6DO)-27
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
Time Needed for Diagnosis:
3 seconds (Low side)
10 seconds (High side)
Malfunction Indicator Light Illumination: Illuminates when malfunctions occur in 2 continuous driving cy-
cles.
Normality Judgment
Judge as OK and clear the NG when both Low side and High side become OK.
Judge as OK when the malfunction criteria below are completed.
6. DTC CLEAR CONDITION
•When the OK idling cycle is completed 40 times in a row
•When “Clear Memory” is performed
7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
•When the OK driving cycle is completed 3 times in a row
•When “Clear Memory” is performed
8. FAIL SAFE
•Intake manifold pressure sensor process: Estimate the pressure from the engine RPM and size of the
throttle opening. When the throttle opening is also NG, fix at 101 kPa (760 mmHg, 29.8 inHg).
•ISC control: ISC feedback amount calculation prohibited
•Purge control: Not allowed to purge
9. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)
Judgment Value
Malfunction Criteria Threshold Value
Low side
Engine speed < 2600 rpm
Throttle position≥ 17°
Output voltage < 1.99 V
Engine load > 0.87 g/rev
High side
Engine speed 500 ←→ 850 rpm
Throttle position < 3.5°
Output voltage≥ 2.71 V
Engine load < 0.6 g/rev
Judgment Value
Malfunction Criteria Threshold Value
Low side
Engine speed < 2600 rpm
Throttle position≥ 17°
Output voltage≥ 1.99 V
Engine load > 0.87 g/rev
High side
Engine speed 500 ←→ 850 rpm
Throttle position < 3.5°
Output voltage < 2.71 V
Engine load < 0.6 g/rev

GD(H6DO)-28
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
R: DTC P0076 INTAKE VALVE CONTROL CIRCUIT LOW (BANK 1)
1. OUTLINE OF DIAGNOSIS
Detect the open circuit of the oil switching solenoid valve.
Judge NG when the current is small even though the output duty is large.
2. ENABLE CONDITIONS
3. GENERAL DRIVING CYCLE
Always perform the diagnosis continuously.
4. DIAGNOSTIC METHOD
Abnormality Judgment
Judge as NG when the continuous time when the following conditions are established is higher than 2 sec-
onds.
Time Needed for Diagnosis: 2 seconds
Malfunction Indicator Light: Illuminates as soon as a malfunction occurs.
Normality Judgment
Judge as OK and clear the NG when the continuous time when the following conditions are established are
more than 2 seconds.
5. DTC CLEAR CONDITION
•When the OK idling cycle is completed 40 times in a row
•When “Clear Memory” is performed
6. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
•When the OK driving cycle is completed 3 times in a row
•When “Clear Memory” is performed
7. FAIL SAFE
None
8. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)
Secondary Parameters Enable Conditions
Battery voltage≥ 10.9 V
Judgment Value
Malfunction Criteria Threshold Value
Duty ratio≥ 30%
Control current < 0.026 A
Judgment Value
Malfunction Criteria Threshold Value
Oil switching solenoid valve current tar-
get current value – oil switching solenoid
valve current value
< 0.08 A
Control current≥ 0.11 A