2004 SUBARU FORESTER ignition

EN(H4SO)-250
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Start the engine, and warm-up the engine.
2) Turn the ignition switch to OFF.
3) Disconnect the connector from TCM.
4) Turn the ignition switch to ON.
5) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 15 (+) — Chassis ground (
−):Is the voltage less than 3 V? Go to step 2.Repair battery
short circuit in har-
ness between
ECM and TCM
connector. After
repair, replace the
ECM. FU(H4SO)-44,
Engine Control
Module (ECM).>
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 15 (+) — Chassis ground (
−):Is the voltage more than 10 V
by shaking the ECM harness
and connector?Repair the battery
short circuit in har-
ness between
ECM and TCM
connector. After
repair, replace the
ECM. FU(H4SO)-44,
Engine Control
Module (ECM).>Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.

EN(H4SO)-252
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 ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 1 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 2.Go to step 4.
2 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and TCM
connector.Go to step 3.
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>
4 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 and ECM connector.
Connector & terminal
(B136) No. 1 — (B56) No. 5:Is the resistance less than 1
Ω?Go to step 5.Repair the open
circuit in harness
between ECM and
TCM connector.
5 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair ground
short circuit in har-
ness between
ECM and TCM
connector.
6 CHECK POOR CONTACT.
Check poor contact in TCM connector.Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-254
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 ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 18 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 2.Go to step 4.
2 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 18 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and TCM
connector.Go to step 3.
3 CHECK POOR CONTACT.
Check poor contact in ECM connector. Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>
4 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 and ECM connector.
Connector & terminal
(B136) No. 18 — (B56) No. 14:Is the resistance less than 1
Ω?Go to step 5.Repair the open
circuit in harness
between ECM and
TCM connector.
5 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 18 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair ground
short circuit in har-
ness between
ECM and TCM
connector.
6 CHECK POOR CONTACT.
Check poor contact in TCM connector. Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-255
ENGINE (DIAGNOSTIC)
General Diagnostic Table
20.General Diagnostic Table
A: INSPECTION
1. ENGINE
NOTE:
Malfunction of parts other than those listed is also possible. eral.>
Symptom Problem parts
1. Engine stalls during idling.1) Idle air control solenoid valve
2) Manifold absolute pressure sensor
3) Intake air temperature sensor
4) Ignition parts (*1)
5) Engine coolant temperature sensor (*2)
6) Crankshaft position sensor (*3)
7) Camshaft position sensor (*3)
8) Fuel injection parts (*4)
2. Rough idling1) Idle air control solenoid valve
2) Manifold absolute pressure sensor
3) Intake air temperature sensor
4) Engine coolant temperature sensor (*2)
5) Ignition parts (*1)
6) Air intake system (*5)
7) Fuel injection parts (*4)
8) Throttle position sensor
9) Crankshaft position sensor (*3)
10) Camshaft position sensor (*3)
11) Oxygen sensor
12) Fuel pump and fuel pump relay
3. Engine does not return to idle.1) Idle air control solenoid valve
2) Engine coolant temperature sensor
3) Accelerator cable (*6)
4) Throttle position sensor
5) Manifold absolute pressure sensor
6) Intake air temperature sensor
4. Poor acceleration1) Manifold absolute pressure sensor
2) Intake air temperature sensor
3) Throttle position sensor
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)
5. Engine stalls or engine sags or hesitates at
acceleration.1) Manifold absolute pressure sensor
2) 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) Throttle position sensor
9) Fuel pump and fuel pump relay

EN(H4SO)-256
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 the accelerator cable.
2. AUTOMATIC TRANSMISSION
NOTE:
Check general diagnostics table with non-conformity symptom for automatic transmission. 4AT(H4SO)-2, Basic Diagnostic Procedure.>
6. Surging1) Intake manifold pressure sensor
2) Intake air temperature sensor
3) Manifold absolute pressure sensor
4) Engine coolant temperature sensor (*2)
5) Crankshaft position sensor (*3)
6) Camshaft position sensor (*3)
7) Fuel injection parts (*4)
8) Throttle position sensor
9) Fuel pump and fuel pump relay
7. Spark knock1) Intake manifold pressure sensor
2) Intake air temperature sensor
3) Manifold absolute pressure sensor
4) Engine coolant temperature sensor
5) Knock sensor
6) Fuel injection parts (*4)
7) Fuel pump and fuel pump relay
8. After burning in exhaust system1) Intake manifold pressure sensor
2) Intake air temperature sensor
3) Manifold absolute pressure sensor
4) Engine coolant temperature sensor (*2)
5) Fuel injection parts (*4)
6) Fuel pump and fuel pump relay Symptom Problem parts

FUJI HEAVY INDUSTRIES LTD. G8080GE3
2004 FORESTER SERVICE MANUAL QUICK REFERENCE INDEX
ENGINE SECTION 2
This service manual has been prepared
to provide SUBARU service personnel
with the necessary information and data
for the correct maintenance and repair
of SUBARU vehicles.
This manual includes the procedures
for maintenance, disassembling, reas-
sembling, inspection and adjustment of
components and diagnostics for guid-
ance of experienced mechanics.
Please peruse and utilize this manual
fully to ensure complete repair work for
satisfying our customers by keeping
their vehicle in optimum condition.
When replacement of parts during
repair work is needed, be sure to use
SUBARU genuine parts.
All information, illustration and specifi-
cations contained in this manual are
based on the latest product information
available at the time of publication
approval.FUEL INJECTION (FUEL SYSTEM) FU(H4DOTC)
EMISSION CONTROL
(AUX. EMISSION CONTROL DEVICE)EC(H4DOTC)
INTAKE (INDUCTION) IN(H4DOTC)
MECHANICAL ME(H4DOTC)
EXHAUST EX(H4DOTC)
COOLING CO(H4DOTC)
LUBRICATION LU(H4DOTC)
SPEED CONTROL SYSTEM SP(H4DOTC)
IGNITION IG(H4DOTC)
STARTING/CHARGING SYSTEM SC(H4DOTC)
ENGINE (DIAGNOSTIC) EN(H4DOTC)

FU(H4DOTC)-16
FUEL INJECTION (FUEL SYSTEM)
Intake Manifold
19) Disconnect the knock sensor connector.
20) Disconnect the connector from crankshaft posi-
tion sensor.
21) Disconnect the connector from camshaft posi-
tion sensor.
22) Disconnect the connector from AVCS camshaft
position sensor.23) Disconnect the connector from oil flow control
solenoid valve.
24) Disconnect the connector from ignition coil.
25) Disconnect the engine harness fixed by clip (A)
from bracket.
FU-00028
FU-00029
FU-00059
FU-00061
ME-00711
FU-00030
FU-00031
(A)

FU(H4DOTC)-18
FUEL INJECTION (FUEL SYSTEM)
Intake Manifold
4) Connect the connector to the oil pressure switch
(B), crankshaft position sensor (C) and engine
coolant temperature sensor (A).
5) Connect the connector to knock sensor.
6) Connect the connector to crankshaft position
sensor.
7) Connect the connector to camshaft position sen-
sor.8) Connect the connector to AVCS camshaft posi-
tion sensor.
9) Connect the connector to oil flow control sole-
noid valve.
10) Connect the connector to ignition coil.
11) Connect the engine harness with clip (A) to the
bracket.
(A)
(B)
(C)
FU-00027
FU-00028
FU-00029
FU-00059
FU-00061
ME-00711
FU-00030
FU-00031
(A)