2004 SUBARU FORESTER coolant temperature

EN(H4DOTC)-75
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P0121 Throttle/Pedal Position Sensor/
Switch “A” Circuit Range/Perfor-
mance SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE, Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>
P0122 Throttle/Pedal Position Sensor/
Switch “A” Circuit Low Input SENSOR/SWITCH “A” CIRCUIT LOW INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0123 Throttle/Pedal Position Sensor/
Switch “A” Circuit High Input SENSOR/SWITCH “A” CIRCUIT HIGH INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0125 Insufficient Coolant Temperature
For Closed Loop Fuel Control PERATURE FOR CLOSED LOOP FUEL CONTROL, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P0129 Barometric Pressure Too Low LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0131 O
2 Sensor Circuit Low Voltage
(Bank 1 Sensor 1) AGE (BANK 1 SENSOR1), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0132 O
2 Sensor Circuit High Voltage
(Bank 1 Sensor 1) VOLTAGE (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0133 O
2 Sensor Circuit Slow Response
(Bank 1 Sensor 1) RESPONSE (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0134 O
2 Sensor Circuit No Activity
Detected (Bank 1 Sensor 1) ITY DETECTED (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P0137 O
2 Sensor Circuit Low Voltage
(Bank 1 Sensor 2) AGE (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0138 O
2 Sensor Circuit High Voltage
(Bank 1 Sensor 2) VOLTAGE (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0139 O
2 Sensor Circuit Slow Response
(Bank 1 Sensor 2) RESPONSE (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0171 System Too Lean (Bank 1) Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0172 System Too Rich (Bank 1) Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0230 Fuel Pump Primary Circuit Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0244 Turbo/Super Charger Wastegate
Solenoid “A” Range/Performance WASTEGATE SOLENOID “A” RANGE/PERFORMANCE, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0245 Turbo/Super Charger Wastegate
Solenoid “A” Low WASTEGATE SOLENOID “A” LOW, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0246 Turbo/Super Charger Wastegate
Solenoid “A” High WASTEGATE SOLENOID “A” HIGH, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0301 Cylinder 1 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0302 Cylinder 2 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0303 Cylinder 3 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).> DTC Item NOTE

EN(H4DOTC)-111
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0111.Go to step 2.
2 CHECK ENGINE COOLANT.
1) Start the engine and warm-up completely.
2) Measure the engine coolant temperature
using Subaru Select Monitor or OBD-II general
scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. to EN(H4DOTC)-33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the engine coolant tempera-
ture between 75°C (167°F) and
95°C (203°F)?Replace the mass
air flow and intake
air temperature
sensor. FU(H4DOTC)-35,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>Inspect the DTC
P0125 using “List
of Diagnostic Trou-
ble Code (DTC)”.
EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>

EN(H4DOTC)-113
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake air temperature
sensor signal using Subaru Select Monitor or
the OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is engine coolant temperature
more than 55°C (131°F)?Go to step 2.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact in
mass air flow and
intake air tempera-
ture sensor
 Poor contact in
ECM
 Poor contact in
joint connector
2 CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air
flow and intake air temperature sensor.
3) Turn the ignition switch to ON.
4) Read the data of intake air temperature
sensor signal using Subaru Select Monitor or
the OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the value less than −36°C
(−33°F)?Replace the mass
air flow and intake
air temperature
sensor. FU(H4DOTC)-35,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>Repair ground
short circuit in har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.

EN(H4DOTC)-117
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Q: DTC P0117 ENGINE COOLANT TEMPERATURE CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Hard to start
 Erroneous idling
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
WIRING DIAGRAM:
EN-02325
B122
B136 ECM
35 14
E8 ENGINE
COOLANT
TEMPERATURE
SENSOR2
1
1 2
17
18
22
16F74
B200
LHD
LHD
RHD
RHD
LHD LHD
RHD
RHD
E8
12
3
B136
125678
131415169101112
34
17181920
B122B22 : RHD
F61 : LHD
F61
E2
: LHD
B22: RHD
F74
34
12 8910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
12345678
: LHDE3: RHD

EN(H4DOTC)-118
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or the OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is engine coolant temperature
more than 120°C (248°F)?Go to step 2.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact in
engine coolant
temperature sen-
sor
 Poor contact in
ECM
 Poor contact in
coupling connector
 Poor contact in
joint connector
2 CHECK 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 the OBD-II general scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the temperature more than
−40°C (−40°F)?Replace the
engine coolant
temperature sen-
sor. FU(H4DOTC)-29,
Engine Coolant
Temperature Sen-
sor.>Repair ground
short circuit in har-
ness between
engine coolant
temperature sen-
sor and ECM con-
nector.

EN(H4DOTC)-119
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
R: DTC P0118 ENGINE COOLANT TEMPERATURE CIRCUIT HIGH INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Hard to start
 Erroneous idling
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
WIRING DIAGRAM:
EN-02325
B122
B136 ECM
35 14
E8 ENGINE
COOLANT
TEMPERATURE
SENSOR2
1
1 2
17
18
22
16F74
B200
LHD
LHD
RHD
RHD
LHD LHD
RHD
RHD
E8
12
3
B136
125678
131415169101112
34
17181920
B122B22 : RHD
F61 : LHD
F61
E2
: LHD
B22: RHD
F74
34
12 8910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
12345678
: LHDE3: RHD

EN(H4DOTC)-120
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or the OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the value less than −40°C
(−40°F)?Go to step 2.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact in
engine coolant
temperature sen-
sor
 Poor contact in
ECM
 Poor contact in
coupling connector
 Poor contact in
joint connector
2 CHECK 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 battery
short circuit in har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.Go to step 3.
3 CHECK 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 battery
short circuit in har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.Go to step 4.
4 CHECK 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:
 Open circuit in
harness between
ECM and engine
coolant tempera-
ture sensor con-
nector
 Poor contact in
engine coolant
temperature sen-
sor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
 Poor contact in
joint connector

EN(H4DOTC)-121
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK 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. FU(H4DOTC)-29,
Engine Coolant
Temperature Sen-
sor.>Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and engine
coolant tempera-
ture sensor con-
nector
 Poor contact in
engine coolant
temperature sen-
sor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
 Poor contact in
joint connector Step Check Yes No