Page 1289 of 2453
EN(H6DO)(diag)-128
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK HARNESS BETWEEN ECM AND OIL
SWITCHING SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
switching solenoid valve.
3) Measure the resistance between oil switch-
ing solenoid valve and engine ground.
Connector & terminal
(E70) No. 1 — Engine ground:
(E70) No. 2 — Engine ground:
Is the resistance more than 1
MΩ?
Go to step 2.Repair the short
circuit between
ECM and oil
switching solenoid
valve connector.
2CHECK OIL SWITCHING SOLENOID VALVE.
1) Remove the oil switching solenoid valve
connector.
2) Measure the resistance between oil switch-
ing solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:
Is the resistance between 6 —
12 Ω?
Repair the poor
contact of ECM
and oil switching
solenoid valve.
Replace the oil
switching solenoid
valve.
ME(H6DO)-78, Oil
Switching Sole-
noid Valve.>
Page 1290 of 2453
EN(H6DO)(diag)-129
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
V: DTC P0101 MASS OR VOLUME AIR FLOW CIRCUIT RANGE/PERFOR-
MANCE
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION
RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Erroneous idling
•Engine stalls.
•Poor driving performance
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
OPERATION, Clear Memory Mode.> and Inspection Mode
Mode.>.
WIRING DIAGRAM:
EN-03660
B3
BATTERY
E
B424
1
B3
MASS AIR FLOW AND INTAKEAIR TEMPERATURE SENSOR
ECMB135
SBF-7
123453412
56
B47
**
2435
3418263035
MAIN RELAY
B47
12
46
35
B424
12345678
* : TERMINAL NO. OPTIONAL ARRANGEMENT
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
Page 1291 of 2453
EN(H6DO)(diag)-130
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Check the appro-
priate DTC using
the “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
NOTE:In this case, it is
not necessary to
inspect DTC
P0101.
Replace the mass
air flow and intake
air temperature
sensor.
FU(H6DO)-23,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Page 1292 of 2453
EN(H6DO)(diag)-131
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
W: DTC P0102 MASS OR VOLUME AIR FLOW CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
•Immediately at fault recognition
•GENERAL DESCRIPTION
LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Erroneous idling
•Engine stalls.
•Poor driving performance
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
OPERATION, Clear Memory Mode.> and Inspection Mode
Inspection Mode.>.
WIRING DIAGRAM:
EN-03660
B3
BATTERY
E
B424
1
B3
MASS AIR FLOW AND INTAKEAIR TEMPERATURE SENSOR
ECMB135
SBF-7
123453412
56
B47
**
2435
3418263035
MAIN RELAY
B47
12
46
35
B424
12345678
* : TERMINAL NO. OPTIONAL ARRANGEMENT
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
Page 1293 of 2453

EN(H6DO)(diag)-132
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CONNECT SUBARU SELECT MONITOR OR
THE GENERAL SCAN TOOL, AND READ
DATA.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor or gen-
eral scan tool to data link connector.
3) Turn the ignition switch to ON, and the Sub-
aru Select Monitor power switch to ON.
4) Start the engine.
5) Read the voltage of mass air flow sensor
using Subaru Select Monitor or general scan
tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the voltage 0.2 — 4.7 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time. Tempo-
rary poor contact
of connector or
harness may be
the cause. Repair
the harness or
connector in mass
air flow sensor.
NOTE:
In this case, repair
the following item:
•Open or
ground short
circuit of har-
ness between
mass air flow
sensor and
ECM connector
•Poor contact
of mass air flow
sensor or ECM
connector
Go to step 2.
2CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground while engine is idling.
Connector & terminal
(B135) No. 26 (+) — Chassis ground (–):
Is the voltage more than 0.2 V? Go to step 4.Go to step 3.
3CHECK INPUT SIGNAL FOR ECM (USING
SUBARU SELECT MONITOR).
Measure the voltage between ECM connector
and chassis ground while engine is idling.
Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with Subaru
Select Monitor?
Repair poor con-
tact in ECM con-
nector.
Replace the ECM.
FU(H6DO)-32,
Engine Control
Module (ECM).>
4CHECK POWER SUPPLY TO MASS AIR
FLOW SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air
flow sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between mass air flow
sensor connector and chassis ground.
Connector & terminal
(B3) No. 1 (+) — Chassis ground (–):
Is the voltage more than 5 V? Go to step 5.Repair the open
circuit between
mass air flow sen-
sor and main relay.
5CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness
between ECM and mass air flow sensor con-
nector.
Connector & terminal
(B135) No. 26 — (B3) No. 3:
(B135) No. 34 — (B3) No. 2:
(B135) No. 30 — (B3) No. 5:
Is the resistance less than 1
Ω?
Go to step 6.Repair the open
circuit between
ECM and mass air
flow sensor con-
nector.
Page 1294 of 2453
EN(H6DO)(diag)-133
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
6CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B135) No. 26 — Chassis ground:
(B135) No. 34 — Chassis ground:
(B135) No. 30 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 7.Repair the ground
short circuit
between ECM and
mass air flow sen-
sor connector.
7CHECK POOR CONTACT.
Check poor contact of mass air flow sensor
connector.
Is there poor contact in mass
air flow sensor connector?
Repair the poor
contact of mass air
flow sensor con-
nector.
Replace the mass
air flow and intake
air temperature
sensor.
FU(H6DO)-23,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Step Check Yes No
Page 1295 of 2453
EN(H6DO)(diag)-134
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
X: DTC P0103 MASS OR VOLUME AIR FLOW CIRCUIT HIGH INPUT
DTC DETECTING CONDITION:
•Immediately at fault recognition
•GENERAL DESCRIPTION
HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Erroneous idling
•Engine stalls.
•Poor driving performance
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode
OPERATION, Clear Memory Mode.> and Inspection Mode
Inspection Mode.>.
WIRING DIAGRAM:
EN-03660
B3
BATTERY
E
B424
1
B3
MASS AIR FLOW AND INTAKEAIR TEMPERATURE SENSOR
ECMB135
SBF-7
123453412
56
B47
**
2435
3418263035
MAIN RELAY
B47
12
46
35
B424
12345678
* : TERMINAL NO. OPTIONAL ARRANGEMENT
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
Page 1296 of 2453

EN(H6DO)(diag)-135
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CONNECT SUBARU SELECT MONITOR OR
THE GENERAL SCAN TOOL, AND READ
DATA.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor or gen-
eral scan tool to data link connector.
3) Turn the ignition switch to ON, and the Sub-
aru Select Monitor power switch to ON.
4) Start the engine.
5) Read the voltage of mass air flow sensor
using Subaru Select Monitor or general scan
tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the voltage 0.2 — 4.7 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.
Go to step 2.
2CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air-
flow sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between mass air flow
sensor connector and chassis ground.
Connector & terminal
(B3) No. 3 (+) — Chassis ground (–):
Is the voltage more than 5 V? Repair the battery
short circuit of har-
ness between
mass air flow sen-
sor connector and
ECM connector.
Go to step 3.
3CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness
between ECM connector and mass air flow
sensor connector.
Connector & terminal
(B3) No. 2 — (B135) No. 34:
Is the resistance less than 1
Ω?
Replace the mass
air flow sensor.
FU(H6DO)-23,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Repair the open
circuit of harness
between mass air
flow sensor con-
nector and ECM
connector.