2004 SUBARU FORESTER check engine

EN(H4DOTC)-198
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK SPEEDOMETER AND TACHOME-
TER OPERATION IN COMBINATION
METER.Does the speedometer and
tachometer operate normally?Go to step 2.Repair or replace
the combination
meter. 3, Combination
Meter System.>
2 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.(engine OFF)
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage more than 4.75
V?Go to step 3.Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.A tempo-
rary poor contact
of the connector
may be the cause.
N
OTE:
In this case repair
the following:
 Poor contact in
fuel pump connec-
tor
 Poor contact in
coupling connector
3 CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the combination meter connec-
tor (i11) and ECM connector.
3) Turn the ignition switch to ON.
4) Measure the voltage of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage more than 4.75
V?Go to step 4.Repair battery
short circuit
between ECM and
combination meter
connector.
4 CHECK HARNESS BETWEEN ECM AND
FUEL TANK CORD.
1) Turn the ignition switch to OFF.
2) Separate fuel tank cord connector (R57)
and rear wiring harness connector (R15).
3) Measure the resistance between ECM and
fuel tank cord.
Connector & terminal
(B136) No. 20 — (R15) No. 2:Is the resistance less than 5
Ω?Go to step 5.Repair open circuit
between ECM and
fuel tank cord.
5 CHECK HARNESS BETWEEN FUEL TANK
CORD AND CHASSIS GROUND.
Measure the resistance between fuel tank cord
and chassis ground.
Connector & terminal
(R15) No. 3 — Chassis ground:Is the resistance less than 5
Ω?Go to step 6.Repair open circuit
between fuel tank
cord and chassis
ground.
N
OTE:
In this case repair
the following:
Poor contact in
coupling connector
6 CHECK FUEL TANK CORD.
1) Disconnect the connector from fuel level
sensor.
2) Measure the resistance between fuel level
sensor and coupler connector.
Connector & terminal
(R57) No. 3 — (R58) No. 5:Is the resistance less than 10
Ω?Go to step 7.Repair open circuit
between coupling
connector and fuel
level sensor.

EN(H4DOTC)-199
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK FUEL TANK CORD.
1) Disconnect the connector from fuel sub
level sensor.
2) Measure the resistance between fuel level
sensor and fuel sub level sensor.
Connector & terminal
(R58) No. 3 — (R59) No. 2:Is the resistance less than 10
Ω?Go to step 8.Repair open circuit
between fuel level
sensor and fuel
sub level sensor.
8 CHECK FUEL TANK CORD.
Measure the resistance between fuel sub level
sensor and coupler connector.
Connector & terminal
(R57) No. 2 — (R59) No. 1:Is the resistance less than 10
Ω?Go to step 9.Repair open circuit
between coupling
connector and fuel
sub level sensor.
9 CHECK FUEL LEVEL SENSOR.
1) Remove the fuel pump assembly. FU(H4DOTC)-62, Fuel Pump.>
2) While moving the fuel level sensor float up
and down, measure resistance between fuel
level sensor terminals.
Te r m i n a l s
No. 3 — No. 5:Is the resistance more than 53
Ω?Replace the fuel
level sensor. to FU(H4DOTC)-
64, Fuel Level
Sensor.>Go to step 10.
10 CHECK FUEL SUB LEVEL SENSOR.
1) Remove the fuel sub level sensor. FU(H4DOTC)-65, Fuel Sub Level Sensor.>
2) While moving the fuel sub level sensor float
up and down, measure resistance between
fuel sub level sensor terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance more than 45
Ω?Replace the fuel
sub level sensor.
FU(H4DOTC)-65,
Fuel Sub Level
Sensor.>Replace the com-
bination meter.
Combination
Meter Assembly.> Step Check Yes No

EN(H4DOTC)-201
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).>Go to step 2.
2 CHECK FUEL LEVEL SENSOR.
1) Remove the fuel pump assembly. FU(H4DOTC)-62, Fuel Pump.>
2) While moving the fuel level sensor float up
and down, make sure that the resistance
between fuel level sensor terminals changes
smoothly.
Te r m i n a l s
No. 3 — No. 5:Does the resistance change
smoothly between approx. 0.5
— 52 Ω?Go to step 3.Replace the fuel
level sensor. to FU(H4DOTC)-
64, Fuel Level
Sensor.>
3 CHECK FUEL SUB LEVEL SENSOR.
1) Remove the fuel sub level sensor. FU(H4DOTC)-65, Fuel Sub Level Sensor.>
2) While moving the fuel sub level sensor float
up and down, make sure that the resistance
between fuel level sensor terminals changes
smoothly.
Te r m i n a l s
No. 1 — No. 2: Does the resistance change
smoothly between approx. 0.5
— 44 Ω?Repair poor con-
tact in ECM, com-
bination meter and
coupling connec-
tors.Replace the fuel
sub level sensor.
FU(H4DOTC)-65,
Fuel Sub Level
Sensor.>

EN(H4DOTC)-202
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BD:DTC P0483 COOLING FAN RATIONALITY CHECK
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
 Occurrence of noise
 Over-heating
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
NOTE:
If the vehicle, with the engine idling, is placed very close to a wall or another vehicle, preventing normal cool-
ing function, the OBD system may detect malfunction.

EN(H4DOTC)-204
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).>Check the radiator
fan, fan motor and
thermostat and
replace the ther-
mostat when it is
stuck. CO(H4SO)-35,
Radiator Main Fan
and Fan Motor.>
CO(H4SO)-40,
Radiator Sub Fan
and Fan Motor.>

EN(H4DOTC)-206
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 2.Go to step 4.
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
TCM.
3) Measure the resistance of harness
between TCM connector and chassis ground.
Connector & terminal
(B56) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in har-
ness between
ECM and TCM
connector.
3 CHECK POOR CONTACT.
Check poor contact in TCM connector.Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Contact the SUB-
ARU dealer.
4 CHECK HARNESS BETWEEN VEHICLE
SPEED SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from vehicle
speed sensor ECM.
3) Measure the resistance of harness
between vehicle speed sensor connector and
chassis ground.
Connector & terminal
(B17) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair ground
short circuit in har-
ness between
vehicle speed sen-
sor and ECM con-
nector.
5 CHECK POOR CONTACT.
Check poor contact in vehicle speed sensor
connector.Is there poor contact in vehicle
speed sensor connector?Repair poor con-
tact in vehicle
speed sensor con-
nector.Replace the vehi-
cle speed sensor.
Vehicle Speed
Sensor.>

EN(H4DOTC)-208
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 2.Go to step 3.
2 CHECK SPEEDOMETER OPERATION IN
COMBINATION METER.Does speedometer operate
normally?Go to step 3.Check the speed-
ometer. IDI-13, Speedom-
eter.>
3 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the combi-
nation meter.
3) Measure the resistance between ECM and
combination meter connector.
Connector & terminal
(B134) No. 1 — (i11) No. 2:Is the resistance less than 10
Ω?Repair the poor
contact in ECM
connector.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and combi-
nation meter con-
nector
 Poor contact in
ECM connector.
 Poor contact in
combination meter
connector
 Poor contact in
coupling connector

EN(H4DOTC)-210
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
P0506.Go to step 2.
2 CHECK IDLE AIR CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve
from the throttle body. 37, REMOVAL, Idle Air Control Solenoid
Va l ve. >
3) Using an air gun, force air into the idle air
control solenoid valve by-pass air inlet.Confirm
that forced air subsequently escapes from both
main air passage and assist air passage.Does air flow out? Go to step 3.Replace the idle
air control solenoid
valve. FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>
After replace, Go
to step 3.
3 CHECK IDLE AIR CONTROL SOLENOID
VALVE DUTY RATIO.
1) Turn the ignition switch to ON.
2) Start the engine, and warm-up the engine.
3) Turn all accessory switches to OFF.
4) Read the data of idle air control solenoid
duty ratio using Subaru Select Monitor or
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 duty ratio more than 60% Go to step 4.END.
4 CHECK BY-PASS AIR LINE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve
from the throttle body. 37, REMOVAL, Idle Air Control Solenoid
Va l ve. >
3) Remove the throttle body from the intake
manifold. REMOVAL, Throttle Body.>
4) Using an air gun, force air into the solenoid
valve installation area and throttle valve inte-
rior.Confirm that forced air subsequently
escapes from both these areas.Does air flow out? Replace the idle
air control solenoid
valve. FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>Replace the throt-
tle body. FU(H4DOTC)-13,
Throttle Body.>