2004 SUBARU FORESTER turn signal

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(H4DOTC)-53
ENGINE (DIAGNOSTIC)
Malfunction Indicator Light
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 17 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 4.Go to step 2.
2 CHECK POOR CONTACT.Does the malfunction indicator
light come on when shaking or
pulling the ECM connector and
harness?Repair the poor
contact in ECM
connector.Go to step 3.
3 CHECK ECM CONNECTOR.Is the ECM connector correctly
connected?Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Repair the con-
nection of ECM
connector.
4 CHECK HARNESS BETWEEN COMBINA-
TION METER AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Remove the combination meter. IDI-10, Combination Meter Assembly.>
3) Disconnect the connector from ECM and
combination meter.
4) Measure the resistance of harness
between ECM and combination meter connec-
tor.
Connector & terminal
(B134) No. 17 — (i12) No. 1:Is the resistance less than 1
Ω?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 combi-
nation meter con-
nector
 Poor contact in
coupling connector
5 CHECK POOR CONTACT.
Check poor contact in combination meter con-
nector.Is there poor contact in combi-
nation meter connector?Repair poor con-
tact in combination
meter connector.Go to step 6.
6 CHECK HARNESS BETWEEN COMBINA-
TION METER AND IGNITION SWITCH CON-
NECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between combination
meter connector and chassis ground.
Connector & terminal
(i10) No. 9 (+) — Chassis ground (
−):Is the voltage more than 10 V? Replace the board
of combination
meter. 10, Combination
Meter Assembly.>Check the follow-
ing and repair if
necessary.
N
OTE:
 Blown out of
fuse (No. 14)
 Open or short
circuit in harness
between fuse (No.
14) and battery
terminal
 Poor contact in
ignition switch con-
nector

EN(H4DOTC)-61
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK OPERATION OF STARTER MOTOR.Does the starter motor oper-
ate?Go to step 2.Go to step 3.
2 CHECK DTC.Is DTC displayed? EN(H4DOTC)-39, OPERA-
TION, Read Diagnostic Trouble
Code (DTC).>Inspect the rele-
vant DTC using
List of Diagnostic
Trouble Code
(DTC). EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>Go to step 3.
3 CHECK INPUT SIGNAL FOR STARTER MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from starter
motor.
3) Turn the ignition switch to START.
4) Measure the power supply voltage between
starter motor connector terminal and engine
ground.
Connector & terminal
(B14) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 4.Go to step 5.
4 CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of ground cable
between ground cable terminal and engine
ground.Is the resistance less than 5
Ω?Check the starter
motor. SC(H4SO)-6,
Starter.>Repair open circuit
of ground cable.
5 CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition
switch.
3) Measure the power supply voltage between
ignition switch connector and chassis ground.
Connector & terminal
(B72) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 6.Check the follow-
ing and repair if
necessary.
 Brown out
fuse
 Open circuit
in harness
between igni-
tion switch and
battery.
6 CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1) Connect the connector to ignition switch.
2) Turn the ignition switch to START.
3) Measure the voltage between ignition
switch and chassis ground.
Connector & terminal
(B72) No. 3 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair open circuit
between ignition
switch and starter
motor circuit.Go to step 7.
7 CHECK POOR CONTACT.
Check poor contact in ignition switch connec-
tor.Is there poor contact in ignition
switch connector?Repair poor con-
tact in ignition
switch connector.Replace the igni-
tion switch.

EN(H4DOTC)-85
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY TO FRONT OXY-
GEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from front oxygen
(A/F) sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between front oxygen
(A/F) sensor connector and engine ground.
Connector & terminal
(B262) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 2.Repair the power
supply line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
main relay and
front oxygen (A/F)
sensor
 CHECK POOR
CONTACT OF
FRONT OXYGEN
(A/F) SENSOR.
 Poor contact in
main relay connec-
tor
2 CHECK GROUND CIRCUIT FOR ECM.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and engine
ground cable
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor or
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 current more than 0.2 A? Repair poor con-
tact connector.
N
OTE:
In this case repair
the following:
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair the poor
contact in ECM
connector.Go to step 6.

EN(H4DOTC)-86
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 3 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 8.Go to step 7.
7 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 3 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair the poor
contact in ECM
connector.Go to step 8.
8 CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between front oxy-
gen (A/F) sensor connector terminals.
Te r m i n a l s
No. 2 — No. 1:Is the resistance less than 10
Ω?Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open or ground
short circuit in har-
ness between front
oxygen (A/F) sen-
sor and ECM con-
nector
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Replace the front
oxygen (A/F) sen-
sor. FU(H4DOTC)-45,
Front Oxygen (A/
F) Sensor.> Step Check Yes No