
EN(H6DO)(diag)-384
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
8CHECK SENSOR OUTPUT.
1) Connect all the connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal
using Subaru Select Monitor.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the voltage less than 4.63
V?
Go to step 9.Go to step 11.
9CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal
using Subaru Select Monitor.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the voltage less than 4.73
V?
Go to step 10.Go to step 11.
10 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and electronic throttle control.
Is there poor contact? Repair the poor
contact.
Te m p o r a r y p o o r
contact occurred,
but it is normal at
present.
11 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Disconnect the connectors from electronic
throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B134) No. 29 — (E57) No. 3:
(B134) No. 18 — (E57) No. 6:
(B134) No. 28 — (E57) No. 4:
Is the resistance less than 1
Ω?
Go to step 12.Repair the open
circuit of harness
connector.
12 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 3 — Engine ground:
Is the resistance less than 5
Ω?
Go to step 13.Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
13 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (–):
Is the voltage less than 10 V? Go to step 14.Repair the battery
short circuit of har-
ness between
ECM connector
and electronic
throttle control
connector.
14 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the voltage between electronic throt-
tle control connector and engine ground.
Connector & terminal
(E57) No. 6 (+) — Engine ground (–):
(E57) No. 4 (+) — Engine ground (–):
Is the voltage less than 10 V? Go to step 15.Repair the short
circuit of harness
between ECM
connector and
electronic throttle
control connector.
Step Check Yes No

EN(H6DO)(diag)-385
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
15 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B134) No. 18 — (B134) No. 19:
(B134) No. 28 — (B134) No. 19:
Is the resistance more than 1
MΩ?
Go to step 16.Repair the short
circuit to sensor
power supply.
16 CHECK ELECTRONIC THROTTLE CON-
TROL HARNESS.
1) Disconnect the connectors from ECM.
2) Disconnect the connectors from electronic
throttle control.
3) Measure the resistance between electronic
throttle control connector terminals.
Connector & terminal
(E57) No. 6 — (E57) No. 4:
Is the resistance more than 1
MΩ?
Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
Repair the short
circuit of harness.
Step Check Yes No

EN(H6DO)(diag)-387
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of main accelerator pedal
position sensor signal and sub accelerator
pedal position sensor signal using Subaru
Select Monitor.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the voltage more than 0.4 V? Go to step 2.Go to step 3.
2CHECK POOR CONTACT.
Check poor contact of connector between
ECM and accelerator pedal position sensor.
Is there poor contact? Repair the poor
contact.
Go to step 12.
3CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Disconnect the connectors from accelerator
pedal position sensor.
4) Measure the resistance between ECM con-
nector and accelerator pedal position sensor
connector.
Connector & terminal
(B135) No. 23 — (B315) No. 6:
(B135) No. 21 — (B315) No. 4:
(B135) No. 31 — (B315) No. 3:
(B135) No. 22 — (B315) No. 1:
Is the resistance less than 1
Ω?
Go to step 4.Repair the open
circuit of harness
connector.
4CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B135) No. 23 — Chassis ground:
(B135) No. 21 — Chassis ground:
(B135) No. 31 — Chassis ground:
(B135) No. 22 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 5.Repair the ground
short circuit of har-
ness.
5CHECK POWER SUPPLY OF ACCELERA-
TOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 4 (+) — Engine ground (–):
(B315) No. 1 (+) — Engine ground (–):
Is the voltage 4.5 — 5.5 V? Go to step 6.Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
6CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Te r m i n a l s
No. 4 — No. 5:
Is the resistance between 1.2
and 4.8 kΩ?
Go to step 7.Replace the accel-
erator pedal posi-
tion sensor.

EN(H6DO)(diag)-388
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
7CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Te r m i n a l s
No. 1 — No. 2:
Is the resistance between 0.75
and 3.15 kΩ?
Go to step 8.Replace the accel-
erator pedal posi-
tion sensor.
8CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor without depressing the accel-
erator pedal.
Te r m i n a l s
No. 6 — No. 5:
Is the resistance between 0.2
and 0.8 kΩ?
Go to step 9.Replace the accel-
erator pedal posi-
tion sensor.
9CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor without depressing the accel-
erator pedal.
Te r m i n a l s
No. 3 — No. 2:
Is the resistance between 0.15
and 0.63 kΩ?
Go to step 10.Replace the accel-
erator pedal posi-
tion sensor.
10 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor with depressing the accelera-
tor pedal.
Te r m i n a l s
No. 6 — No. 5:
Is the resistance between 0.5
and 2.5 kΩ?
Go to step 11.Replace the accel-
erator pedal posi-
tion sensor.
11 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor with depressing the accelera-
tor pedal.
Te r m i n a l s
No. 3 — No. 2:
Is the resistance between 0.28
and 1.68 kΩ?
Go to step 12.Replace the accel-
erator pedal posi-
tion sensor.
12 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to OFF.
2) Connect all the connectors.
3) Turn the ignition switch to ON.
4) Read the data of main accelerator pedal
position sensor signal and the sub accelerator
pedal position sensor signal using the Subaru
Select Monitor.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the voltage less than 4.8 V? Go to step 13.Go to step 14.
13 CHECK POOR CONTACT.
Check poor contact of connector between
ECM and accelerator pedal position sensor.
Is there poor contact? Repair the poor
contact.
Go to step 18.
Step Check Yes No

EN(H6DO)(diag)-389
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
14 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Disconnect the connectors from accelerator
pedal position sensor.
4) Measure the resistance between ECM con-
nector and accelerator pedal position sensor
connector.
Connector & terminal
(B135) No. 29 — (B315) No. 5:
(B135) No. 30 — (B315) No. 2:
Is the resistance less than 1
Ω?
Go to step 15.Repair the open
circuit of harness
connector.
15 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Measure the resistance between accelera-
tor pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 5 — Engine ground:
(B315) No. 2 — Engine ground:
Is the resistance less than 5
Ω?
Go to step 16.Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
16 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 6 (+) — Engine ground (–):
(B315) No. 3 (+) — Engine ground (–):
Is the voltage less than 6 V? Go to step 17.Repair the battery
short circuit of har-
ness between
ECM connector
and accelerator
pedal position sen-
sor connector.
17 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B135) No. 23 — (B135) No. 21:
(B135) No. 23 — (B135) No. 22:
(B135) No. 31 — (B135) No. 21:
(B135) No. 31 — (B135) No. 22:
Is the resistance more than 1
MΩ?
Go to step 18.Repair the short
circuit to sensor
power supply.
18 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Disconnect the connectors from accelerator
pedal position sensor.
4) Measure the resistance between connector
terminals of accelerator pedal position sensor.
Connector & terminal
(B315) No. 6 — (B315) No. 3:
Is the resistance more than 1
MΩ?
Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
Repair the short
circuit of harness
between ECM
connector and
accelerator pedal
position sensor
connector.
Step Check Yes No

EN(H6DO)(diag)-392
General Diagnostic Table
ENGINE (DIAGNOSTICS)
19.General Diagnostic Table
A: INSPECTION
1. ENGINE
NOTE:
Malfunction of parts other than those listed is also possible.
Symptom Problem parts
1. Engine stalls during idling.
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Ignition parts (*1)
4) Engine coolant temperature sensor (*2)
5) Crankshaft position sensor (*3)
6) Camshaft position sensor (*3)
7) Fuel injection parts (*4)
2. Rough idling
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Ignition parts (*1)
5) Air intake system (*5)
6) Fuel injection parts (*4)
7) Electronic throttle control
8) Crankshaft position sensor (*3)
9) Camshaft position sensor (*3)
10) Oxygen sensor
11) Fuel pump and fuel pump relay
3. Engine does not return to idle.
1) Engine coolant temperature sensor
2) Electronic throttle control
3) Manifold absolute pressure sensor
4) Mass air flow and intake air temperature sensor
5) Accelerator pedal position sensor
6) Oil temperature sensor
4. Poor acceleration
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Electronic throttle control
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
6) Engine coolant temperature sensor (*2)
7) Crankshaft position sensor (*3)
8) Camshaft position sensor (*3)
9) A/C switch and A/C cut relay
10) Engine torque control signal circuit
11) Ignition parts (*1)
12) Accelerator pedal position sensor
13) Oil temperature sensor
5. Engine stalls, engine sags or hesitates at accel-
eration.
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Purge control solenoid valve
7) Fuel injection parts (*4)
8) Electronic throttle control
9) Fuel pump and fuel pump relay

EN(H6DO)(diag)-393
General Diagnostic Table
ENGINE (DIAGNOSTICS)
*1: Check ignition coil & ignitor assembly and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Make sure the secure installation.
*4: Check the fuel injector and fuel pressure regulator.
*5: Inspect air leak in air intake system.
6. Surging
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Fuel injection parts (*4)
7) Electronic throttle control
8) Fuel pump and fuel pump relay
7. Spark knock
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor
4) Knock sensor
5) Fuel injection parts (*4)
6) Fuel pump and fuel pump relay
8. After burning in exhaust system
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor (*2)
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
Symptom Problem parts

FU(H6DO)-32
Engine Control Module (ECM)
FUEL INJECTION (FUEL SYSTEMS)
16.Engine Control Module (ECM)
A: REMOVAL
1) Disconnect the ground cable from battery.
2) Remove the front pillar lower trim and console
side panel lower RH of passenger's side.
3) Detach the floor mat of passenger's seat.
4) Remove the protect cover.
5) Remove the nuts which hold the ECM to the
bracket.
6) Remove the clip (A) from bracket.
B: INSTALLATION
Install in the reverse order of removal.
CAUTION:
•When replacing the ECM, be careful not to
use the wrong spec. ECM to avoid any damage
on the fuel injection system.
•When replacing the ECM, be careful not to
damage the harnesses and connectors.
•When replacing the ECM, immobilizer system
must be registered. To do so, all ignition keys
and ID cards need to be prepared. Refer to the
“IMMOBILIZER TEACHING OPERATION MANU-
AL”.
Tightening torque:
5 N·m (0.5 kgf-m, 3.6 ft-lb)
FU-02090
FU-02682