EN(H6DO)(diag)-148
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
4CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.
Connector & terminal
(B3) No. 4 (+) — Engine ground (–):
Is the voltage more than 3 V? Go to step 5.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Broken wire
between mass
air flow and in-
take air temper-
ature sensor
and ECM con-
nector.
•Poor contact
in mass air flow
and intake air
temperature
sensor
•Poor contact
in ECM
•Poor contact
of coupling con-
nector
•Poor contact
of joint connec-
tor
5CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between mass air flow and intake air tempera-
ture sensor connector and engine ground.
Connector & terminal
(B3) No. 5 — Engine ground:
Is the resistance less than 5
Ω?
Replace the mass
air flow and intake
air temperature
sensor.
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Broken wire
between mass
air flow and in-
take air temper-
ature sensor
and ECM con-
nector.
•Poor contact
in mass air flow
and intake air
temperature
sensor
•Poor contact
in ECM
•Poor contact
of joint connec-
tor
Step Check Yes No
EN(H6DO)(diag)-150
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of engine coolant tempera-
ture sensor signal using 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 engine coolant tempera-
ture above 150°C (302°F) ?
Go to step 2.Repair the poor
contact.
NOTE:
In this case, repair
the following item:
•Poor contact
of engine cool-
ant tempera-
ture sensor
•Poor contact
in ECM
•Poor contact
of coupling con-
nector
•Poor contact
of joint connec-
tor
2CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the engine
coolant temperature sensor.
3) Turn the ignition switch to ON.
4) Read the data of engine coolant tempera-
ture sensor signal using 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 engine coolant tempera-
ture less than –40°C (–40°F) ?
Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
Repair the ground
short circuit of har-
ness between
engine coolant
temperature sen-
sor and ECM con-
nector.
EN(H6DO)(diag)-152
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of engine coolant tempera-
ture sensor signal using 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 engine coolant tempera-
ture less than –40°C (–40°F) ?
Go to step 2.Repair the poor
contact.
NOTE:
In this case, repair
the following item:
•Poor contact
of engine cool-
ant tempera-
ture sensor
•Poor contact
in ECM
•Poor contact
of coupling con-
nector
•Poor contact
of joint connec-
tor
2CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the engine
coolant temperature sensor.
3) Measure the voltage between engine cool-
ant temperature sensor connector and engine
ground.
Connector & terminal
(E8) No. 2 (+) — Engine ground (–):
Is the voltage more than 10 V? Repair the battery
short circuit of har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.
Go to step 3.
3CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between engine cool-
ant temperature sensor connector and engine
ground.
Connector & terminal
(E8) No. 2 (+) — Engine ground (–):
Is the voltage more than 10 V? Repair the battery
short circuit of har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.
Go to step 4.
EN(H6DO)(diag)-153
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
4CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
Measure the voltage between engine coolant
temperature sensor connector and engine
ground.
Connector & terminal
(E8) No. 2 (+) — Engine ground (–):
Is the voltage more than 4 V? Go to step 5.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
engine coolant
temperature
sensor connec-
tor
•Poor contact
of engine cool-
ant tempera-
ture sensor
connector
•Poor contact
in ECM connec-
tor
•Poor contact
of coupling con-
nector
•Poor contact
of joint connec-
tor
5CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between engine coolant temperature sensor
connector and engine ground.
Connector & terminal
(E8) No. 1 — Engine ground:
Is the resistance less than 5
Ω?
Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
engine coolant
temperature
sensor connec-
tor
•Poor contact
of engine cool-
ant tempera-
ture sensor
connector
•Poor contact
in ECM connec-
tor
•Poor contact
of coupling con-
nector
•Poor contact
of joint connec-
tor
Step Check Yes No
EN(H6DO)(diag)-156
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) 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 more than 0.4 V? Go to step 2.Go to step 3.
2CHECK POOR CONTACT.
Check poor contact in connector between
ECM and electronic throttle control.
Is there poor contact in con-
nector between ECM and elec-
tronic throttle control?
Repair the poor
contact.
Te m p o r a r y p o o r
contact occurred,
but it is normal at
present.
3CHECK 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. 18 — (E57) No. 6:
(B134) No. 19 — (E57) No. 5:
Is the resistance less than 1
Ω?
Go to step 4.Repair the open
circuit of harness
connector.
4CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B134) No. 18 — Chassis ground:
(B134) No. 19 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 5.Repair the chas-
sis short circuit of
harness.
5CHECK POWER SUPPLY OF 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 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 SHORT CIRCUIT INSIDE THE ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 6 — Engine ground:
Is the resistance more than
10Ω?
Repair the poor
contact of elec-
tronic throttle con-
trol connector.
Replace the accel-
erator pedal posi-
tion sensor if
defective.
Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
EN(H6DO)(diag)-159
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) 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 2.Go to step 3.
2CHECK POOR CONTACT.
Check poor contact in connector between
ECM and electronic throttle control.
Is there poor contact in con-
nector between ECM and elec-
tronic throttle control?
Repair the poor
contact.
Te m p o r a r y p o o r
contact occurred,
but it is normal at
present.
3CHECK 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. 18 — (E57) No. 6:
(B134) No. 29 — (E57) No. 3:
Is the resistance less than 1
Ω?
Go to step 4.Repair the open
circuit of harness
connector.
4CHECK 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 5.Repair poor con-
tact in ECM con-
nector. Replace
the ECM if defec-
tive.
Engine Control
Module (ECM).>
5CHECK SENSOR OUTPUT POWER SUP-
PLY.
Measure the voltage between electronic throt-
tle control connector and engine ground.
Connector & terminal
(E57) No. 6 (+) — Engine ground (–):
Is the voltage less than 10 V? Replace the elec-
tronic throttle con-
trol.
Throttle Body.>
Repair the battery
short circuit of har-
ness between
ECM connector
and electronic
throttle control
connector.
EN(H6DO)(diag)-160
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
AH:DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP
FUEL CONTROL
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION
TROUBLE SYMPTOM:
Engine would not return to idling.
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? 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).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0125.
Go to step 2.
2CHECK TIRE SIZE.Is the tire size as specified?
and the same size as other
three wheels?
Go to step 3.Replace the tire.
3CHECK ENGINE COOLANT.
Check the following items:
•Amount of engine coolant
•Engine coolant freeze
•Contamination of engine coolant
Is the engine coolant normal? Go to step 4.Fill or replace the
engine coolant.
INSPECTION,
Engine Coolant.>
4CHECK THERMOSTAT.Does the thermostat remain
opened?
Replace the ther-
mostat.
Thermostat.>
Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
EN(H6DO)(diag)-162
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)”.
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
Measure the resistance between engine cool-
ant temperature sensor terminals when the
engine coolant is cold and after warmed-up.
Te r m i n a l s
No. 1 — No. 2:
Is the resistance of engine
coolant temperature sensor dif-
ferent between when engine
coolant is cold and after
warmed-up?
Contact with SOA
Service Center.
Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>