Page 1271 of 2453

EN(H6DO)(diag)-110
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
WIRING DIAGRAM:
EN-03737
SBF-5
B47
12
35
46
A3D1D7D2A5D3
2
3736353452B21
E2
ECM
B11B1B10B6B7C2C3B8B9
413
E24
2
431
E47
E3B22
8
56E3
B222134
B47
3456
12
B22
1234567891011 121314 15 16
3412
E47E24
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
B:
B21
123412131415567816171819910 1120212223 24 25 2627 28 29 3031 32 33
3534 37363938 41404342 4445 47464948 51505352 54
EE
B135B:B136C:B137D:B134A:
7
FRONTOXYGEN(A/F)SENSOR LH
FRONTOXYGEN(A/F)SENSOR RH
MAIN RELAYBATTERY
B136
16101112131415252430
9871718192028212223293231
123456
2726333435
C:
B137
85610 11 12 13 14 157213416
3019 20 2228 29
91718 2521 23 243126 27
D:B122
34561278
*: TERMINAL NO. OPTIONAL ARRANGEMENT
**
B122
A:B134
85610 11 12 13 14 157213416
3019 20 2228 29
91718252123 24323126 2733 34
Step Check Yes No
1CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 6 (+) — Chassis ground (–):
(B135) No. 7 (+) — Chassis ground (–):
Is the voltage more than 8 V? Go to step 2.Go to step 3.
Page 1272 of 2453

EN(H6DO)(diag)-111
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
2CHECK FRONT OXYGEN (A/F) SENSOR
HEATER CURRENT.
1) Turn the ignition switch to OFF.
2) Repair the battery short circuit of harness
between ECM and front oxygen (A/F) sensor
connector.
3) Turn the ignition switch to ON.
4) Read the data of front oxygen (A/F) sensor
heater current 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 current more than 2.3 A? Replace the ECM.
FU(H6DO)-32,
Engine Control
Module (ECM).>
END.
3CHECK OUTPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 6 (+) — Chassis ground (–):
(B135) No. 7 (+) — Chassis ground (–):
Does the voltage change by
shaking the ECM harness and
connector?
Repair the battery
short circuit of har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.
END.
Step Check Yes No
Page 1274 of 2453
EN(H6DO)(diag)-113
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
WIRING DIAGRAM:
EN-03738
SBF-5
B47
12
35
46
A3D7D1D2A5D3
2
373635363452B21
E2
ECM
C5B15B4C4B30
431
REAROXYGENSENSOR LH
E25
2
431
REAROXYGENSENSOR RH
E61
E3B22
14
1315E3
B221011129
B424
B47
3456
12
B21
123412131415567816171819910 1120212223 24 25 2627 28 29 3031 32 33
3534 37363938 41404342 4445 47464948 51505352 54
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
B:B134
56 7821943102422 23 2511 12 13 14 1526 2728
16 1718 19 20 2133 34293230 31
A:
16
B134A:
B135B:
B136C:
B137D:
B22
1234567891011 121314 15 16
B136
567821943102422 23 2511 12 13141526 2728
1617 18 19 20 2133 3429323031 35
C:B137
5678219431022 2311 12 13 14 1524 2526
16 1718 19 20 2127 28 29 30 31
D:
12345678
B424
B122
3412
E25E61
MAIN RELAYBATTERY
EE
* : TERMINAL NO. OPTIONAL ARRANGEMENT
***B1
**
B122
Page 1278 of 2453

EN(H6DO)(diag)-117
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
WIRING DIAGRAM:
EN-03738
SBF-5
B47
12
35
46
A3D7D1D2A5D3
2
373635363452B21
E2
ECM
C5B15B4C4B30
431
REAROXYGENSENSOR LH
E25
2
431
REAROXYGENSENSOR RH
E61
E3B22
14
1315E3
B221011129
B424
B47
3456
12
B21
123412131415567816171819910 1120212223 24 25 2627 28 29 3031 32 33
3534 37363938 41404342 4445 47464948 51505352 54
B135
567821943102422 23 2511 12 13 14 1526 2728
16 17 18 1920 2129 30 31 32 33 34 35
B:B134
56 7821943102422 23 2511 12 13 14 1526 2728
16 1718 19 20 2133 34293230 31
A:
16
B134A:
B135B:
B136C:
B137D:
B22
1234567891011 121314 15 16
B136
567821943102422 23 2511 12 13141526 2728
1617 18 19 20 2133 3429323031 35
C:B137
5678219431022 2311 12 13 14 1524 2526
16 1718 19 20 2127 28 29 30 31
D:
12345678
B424
B122
3412
E25E61
MAIN RELAYBATTERY
EE
* : TERMINAL NO. OPTIONAL ARRANGEMENT
***B1
**
B122
Step Check Yes No
1CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 5 (+) — Chassis ground (–):
Is the voltage more than 8 V? Go to step 2.Go to step 3.
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 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