check engine SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC)-279
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
P1312.Replace the
exhaust tempera-
ture sensor. to FU(H4DOTC)-
49, Exhaust Tem-
perature Sensor.>

EN(H4DOTC)-281
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OPERATION OF STARTER MOTOR.Does the starter motor operate
when ignition switch to
START?Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open or ground
short circuit in har-
ness between
ECM and starter
motor connector.
 Poor contact in
ECM connector.Check starter
motor circuit. to EN(H4DOTC)-
60, STARTER
MOTOR CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.>

EN(H4DOTC)-283
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
P1544.Go to step 2.
2 CHECK EXHAUST SYSTEM.
Check exhaust system parts.
NOTE:
Check the following items:
 Loose installation of exhaust manifold
 Cracks or hole of exhaust manifold
 Loose installation of front oxygen (A/F) sen-
sorIs there a fault in exhaust sys-
tem?Repair or replace
failure, then
replace the precat-
alytic converter.Contact the SUB-
ARU dealer.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

EN(H4DOTC)-286
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 19 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair the poor
contact in ECM
connector.Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND
MAIN FUSE BOX CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and chassis ground.
Connector & terminal
(B135) No. 19 — Chassis ground:Is the resistance less than 10
Ω?Repair ground
short circuit in har-
ness between
ECM connector
and battery termi-
nal.Go to step 3.
3 CHECK FUSE SBF-5.Is the fuse blown out? Replace the fuse. Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and battery
 Poor contact in
ECM connector.
 Poor contact in
battery terminal

EN(H4DOTC)-288
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(B134) No. 18 — (E38) No. 1:
(B134) No. 28 — (E38) No. 2:Is the resistance less than 1
Ω?Go to step 2.Repair open circuit
in harness
between ECM and
oil flow control
solenoid valve
connector.
N
OTE:
In this case, repair
the following:
 Open circuit in
harness between
ECM and oil flow
control solenoid
valve connector
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
Measure the resistance between ECM and oil
flow control solenoid valve.
Connector & terminal
(E38) No. 1 — Engine ground:
(E38) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair short circuit
between ECM and
oil flow control
solenoid valve
connector.
3 CHECK OIL FLOW CONTROL SOLENOID
VALVE.
1) Remove the oil flow control solenoid valve
connector.
2) Measure the resistance between oil flow
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 6 — 12 Ω? Repair poor con-
tact in ECM and oil
flow control sole-
noid valve.Replace the oil
flow control sole-
noid valve. to ME(H4DOTC)-
68, Camshaft.>

EN(H4DOTC)-290
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(B134) No. 18 — (E38) No. 1:
(B134) No. 28 — (E38) No. 2:Is the resistance less than 1
Ω?Go to step 2.Repair open circuit
in harness
between ECM and
oil flow control
solenoid valve
connector.
N
OTE:
In this case, repair
the following:
 Open circuit in
harness between
ECM and oil flow
control solenoid
valve connector
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(E38) No. 1 — Engine ground:
(E38) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair short circuit
between ECM and
oil flow control
solenoid valve
connector.
3 CHECK OIL FLOW CONTROL SOLENOID
VALVE.
1) Remove the oil flow control solenoid valve
connector.
2) Measure the resistance between oil flow
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 6 — 12 Ω? Repair poor con-
tact in ECM and oil
flow control sole-
noid valve.Replace the oil
flow control sole-
noid valve. to ME(H4DOTC)-
68, Camshaft.>

EN(H4DOTC)-292
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(B134) No. 19 — (E37) No. 1:
(B134) No. 29 — (E37) No. 2:Is the resistance less than 1
Ω?Go to step 2.Repair open circuit
in harness
between ECM and
oil flow control
solenoid valve
connector.
N
OTE:
In this case, repair
the following:
 Open circuit in
harness between
ECM and oil flow
control solenoid
valve connector
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
Measure the resistance between ECM and oil
flow control solenoid valve.
Connector & terminal
(E37) No. 1 — Engine ground:
(E37) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair short circuit
between ECM and
oil flow control
solenoid valve
connector.
3 CHECK OIL FLOW CONTROL SOLENOID
VALVE.
1) Remove the oil flow control solenoid valve
connector.
2) Measure the resistance between oil flow
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 6 — 12 Ω? Repair poor con-
tact in ECM and oil
flow control sole-
noid valve.Replace the oil
flow control sole-
noid valve. to ME(H4DOTC)-
68, Camshaft.>

EN(H4DOTC)-294
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(B134) No. 19 — (E37) No. 1:
(B134) No. 29 — (E37) No. 2:Is the resistance less than 1
Ω?Go to step 2.Repair open circuit
in harness
between ECM and
oil flow control
solenoid valve
connector.
N
OTE:
In this case, repair
the following:
 Open circuit in
harness between
ECM and oil flow
control solenoid
valve connector
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND OIL
FLOW CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and oil
flow control solenoid valve.
3) Measure the resistance between ECM and
oil flow control solenoid valve.
Connector & terminal
(E37) No. 1 — Engine ground:
(E37) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair short circuit
between ECM and
oil flow control
solenoid valve
connector.
3 CHECK OIL FLOW CONTROL SOLENOID
VALVE.
1) Remove the oil flow control solenoid valve
connector.
2) Measure the resistance between oil flow
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 6 — 12 Ω? Repair poor con-
tact in ECM and oil
flow control sole-
noid valve.Replace the oil
flow control sole-
noid valve. to ME(H4DOTC)-
68, Camshaft.>

EN(H4DOTC)-296
ENGINE (DIAGNOSTIC)
General Diagnostic Table
*1: Check ignition coil & ignitor ASSY and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Ensure the secure installation.
*4: Check fuel injector, fuel pressure regulator and fuel filter.
*5: Inspect air leak in air intake system.
*6: Adjust accelerator cable. 6. Surging1) 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) Fuel injection parts (*4)
7) Throttle position sensor
8) Fuel pump and fuel pump relay
7. Spark knock1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature 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 system1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay Symptom Problem parts

ENGINE (DIAGNOSTIC)
EN(H4DOTC 2.5)
Page
1. Basic Diagnostics Procedure ......................................................................2
2. Check List for Interview ...............................................................................3
3. General Description ....................................................................................5
4. Electrical Component Location ...................................................................8
5. Engine Control Module (ECM) I/O Signal .................................................17
6. Engine Condition Data ..............................................................................22
7. Data Link Connector .................................................................................23
8. OBD-II General Scan Tool ........................................................................24
9. Subaru Select Monitor...............................................................................27
10. Read Diagnostic Trouble Code (DTC) ......................................................34
11. Inspection Mode ........................................................................................35
12. Drive Cycle ................................................................................................40
13. Clear Memory Mode..................................................................................42
14. Compulsory Valve Operation Check Mode ...............................................43
15. Malfunction Indicator Light ........................................................................45
16. Diagnostics for Engine Starting Failure .....................................................54
17. List of Diagnostic Trouble Code (DTC) .....................................................65
18. Diagnostic Procedure with Diagnostic Trouble Code (DTC) .....................70
19. General Diagnostic Table........................................................................258