2004 SUBARU FORESTER replace disc

EN(H4DOTC 2.5)-53
ENGINE (DIAGNOSTIC)
Malfunction Indicator Light
Step Check Yes No
1 CHECK TEST MODE CONNECTOR.
1) Disconnect the test mode connectors
2) Turn the ignition switch to ON.Does the malfunction indicator
light blink?Go to step 2.System is in good
order.
N
OTE:
Malfunction indica-
tor light blinks at a
cycle of 3 Hz when
test mode connec-
tor is connected.
2 CHECK HARNESS BETWEEN ECM CON-
NECTOR AND ENGINE GROUND TERMI-
NAL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B137) No. 15 — Chassis ground:Is the resistance less than 5
Ω?Repair the short
circuit in harness
between ECM and
test mode connec-
tor.Replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>

EN(H4DOTC 2.5)-56
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK BATTERY.
Check the battery voltage.Is the voltage more than 12 V? Go to step 2.Charge or replace
the battery.
2 CHECK OPERATION OF STARTER MOTOR.Does the starter motor oper-
ate?Check ECM power
supply and ground
line. EN(H4DOTC 2.5)-
57, CHECK
POWER SUPPLY
AND GROUND
LINE OF ENGINE
CONTROL MOD-
ULE (ECM), Diag-
nostics for Engine
Starting Failure.>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 (
−):
NOTE:
 For AT model, shift the select lever to “P” or
“N” range.
 For MT model, depress the clutch pedal.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) Disconnect the terminal from starter motor.
3) 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) Disconnect the connector from ignition
switch.
2) 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.Repair open circuit
in harness
between ignition
switch and bat-
tery, and check
fuse SBF No. 4
and SBF No. 1.
6 CHECK IGNITION SWITCH.
1) Disconnect the connector from ignition
switch.
2) Measure the resistance between ignition
switch terminals while turning the ignition
switch to START.
Te r m i n a l s
No. 1 — No. 3:Is the resistance less than 5
Ω?Repair the poor
contact in ignition
switch.Replace the igni-
tion switch.

EN(H4DOTC 2.5)-58
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the main relay.
3) Connect the battery to main relay terminals
No. 1 and No. 2.
4) Measure the resistance between main relay
terminals.
Te r m i n a l s
No. 3 — No. 5:
No. 4 — No. 6:Is the resistance less than 10
Ω?Go to step 2.Replace the main
relay.
2 CHECK GROUND CIRCUIT FOR ECM.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:
(B134) No. 34 — Chassis ground:
(B135) No. 1 — Chassis ground:
(B135) No. 4 — Chassis ground:
(B135) No. 12 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 7 — Chassis ground: Is the resistance less than 5
Ω?Go to step 3.Repair open circuit
in harness
between ECM con-
nector and engine
ground terminal.
3 CHECK INPUT VOLTAGE OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 19 (+) — Chassis ground (
−):
(B137) No. 14 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 4.Repair open or
ground short cir-
cuit of power sup-
ply circuit.
4 CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.
Connector & terminal
(B47) No. 1 (+) — Chassis ground (
−):
(B47) No. 5 (+) — Chassis ground (
−):
(B47) No. 6 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 5.Repair open or
ground short circuit
in harness of power
supply circuit.
5 CHECK INPUT VOLTAGE OF ECM.
1) Connect the main relay connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 5 (+) — Chassis ground (
−):
(B135) No. 6 (+) — Chassis ground (
−):
(B137) No. 16 (+) — Chassis ground (
−):Is the voltage more than 10 V? Check ignition
control system.
EN(H4DOTC 2.5)-
59, IGNITION
CONTROL SYS-
TEM, Diagnostics
for Engine Start-
ing Failure.>Repair open or
ground short circuit
in harness
between ECM con-
nector and main
relay connector.

EN(H4DOTC 2.5)-60
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK SPARK PLUG CONDITION.
1) Remove the spark plug. IG(H4DOTC)-6, INSTALLATION, Spark Plug.>
2) Check the spark plug condition. IG(H4DOTC)-6, INSPECTION, Spark Plug.>Is the spark plug’s status OK? Go to step 2.Replace the spark
plug.
2 CHECK IGNITION SYSTEM FOR SPARKS.
1) Connect the spark plug to ignition coil.
2) Release the fuel pressure. FU(H4DOTC 2.5)-45, RELEASING OF FUEL
PRESSURE, OPERATION, Fuel.>
3) Contact the spark plug’s thread portion on
engine.
4) While opening the throttle valve fully, crank
the engine to check that spark occurs at each
cylinder.Does spark occur at each cyl-
inder?Check fuel pump
system. EN(H4DOTC 2.5)-
62, FUEL PUMP
CIRCUIT, Diag-
nostics for Engine
Starting Failure.>Go to step 3.
3 CHECK POWER SUPPLY CIRCUIT FOR IG-
NITION COIL & IGNITOR ASSY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition coil
& ignitor ASSY.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
ignition coil & ignitor ASSY connector and
engine ground.
Connector & terminal
(E31) No. 3 (+) — Engine ground (
−):
(E32) No. 3 (+) — Engine ground (
−):
(E33) No. 3 (+) — Engine ground (
−):
(E34) No. 3 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 4.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ignition coil & igni-
tor ASSY, and igni-
tion switch
connector
 Poor contact in
coupling connector
4 CHECK HARNESS OF IGNITION COIL & IG-
NITOR ASSY GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ignition
coil & ignitor ASSY connector and engine
ground.
Connector & terminal
(E31) No. 2 — Engine ground:
(E32) No. 2 — Engine ground:
(E33) No. 2 — Engine ground:
(E34) No. 2 — Engine ground:Is the resistance less than 5
Ω?Go to step 5.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ignition coil & igni-
tor ASSY connec-
tor and engine
ground terminal
5 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSY CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from ignition coil
& ignitor ASSY.
4) Measure the resistance of harness
between ECM and ignition coil & ignitor ASSY
connector.
Connector & terminal
(B135) No. 15 — (E34) No. 1:
(B135) No. 16 — (E33) No. 1:
(B135) No. 17 — (E32) No. 1:
(B135) No. 18 — (E31) No. 1:Is the resistance less than 1
Ω?Go to step 6.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 OPEN CIR-
CUIT IN HAR-
NESS BETWEEN
ECM AND IGNI-
TION COIL &
IGNITOR ASSY
CONNECTOR.
 Poor contact in
coupling connector

EN(H4DOTC 2.5)-64
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
2 CHECK POWER SUPPLY TO EACH FUEL
INJECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
fuel injector terminal and engine ground.
Connector & terminal
#1 (E5) No. 2 (+) — Engine ground (
−):
#2 (E16) No. 2 (+) — Engine ground (
−):
#3 (E6) No. 2 (+) — Engine ground (
−):
#4 (E17) No. 2 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 3.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
main relay and fuel
injector connector
 Poor contact in
main relay connec-
tor
 Poor contact in
coupling connector
 Poor contact in
fuel injector con-
nector
3 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and fuel injector connector.
Connector & terminal
(B136) No. 6 — (E5) No. 1:
(B136) No. 5 — (E16) No. 1:
(B136) No. 4 — (E6) No. 1:
(B136) No. 3 — (E17) No. 1:Is the resistance less than 1
Ω?Go to step 4.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and fuel
injector connector
 Poor contact in
coupling connector
4 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
(B136) No. 3 — Chassis ground:
(B136) No. 4 — Chassis ground:
(B136) No. 5 — Chassis ground:
(B136) No. 6 — Chassis ground:Is the resistance less than 1
Ω?Repair ground
short circuit in har-
ness between
ECM and fuel
injector connector.Go to step 5.
5 CHECK EACH FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between each fuel
injector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 5 — 20 Ω? Go to step 6.Replace the faulty
fuel injector.
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Inspection using
“General Diagnos-
tic Table”. EN(H4DOTC 2.5)-
258, INSPEC-
TION, General
Diagnostic Table.> Step Check Yes No

EN(H4DOTC 2.5)-76
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK GROUND CIRCUIT FOR ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) 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 2.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
2 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of rear oxygen (A/F) sensor
heater current 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”. 2.5)-27, 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 the connec-
tor.
NOTE:
In this case repair
the following:
 Poor contact in
rear oxygen sen-
sor connector
 Poor contact in
rear oxygen sen-
sor connecting
harness connector
 Poor contact in
ECM connector.Go to step 3.
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) 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 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear oxygen
sensor.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Repair battery short
circuit in harness
between ECM and
rear oxygen sensor
connector. After
repair, replace the
ECM. FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>

EN(H4DOTC 2.5)-77
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK POWER SUPPLY TO REAR OXY-
GEN SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear oxygen
sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between rear oxygen
sensor connector and chassis ground.
Connector & terminal
(B18) No. 2 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 7.Repair the power
supply line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
main relay and
rear oxygen sen-
sor connector
 Poor contact in
rear oxygen sen-
sor connector
 Poor contact in
coupling connector
7 CHECK REAR OXYGEN SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between rear oxy-
gen sensor connector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 30
Ω?Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
rear oxygen sen-
sor and ECM con-
nector
 Poor contact in
rear oxygen sen-
sor connector
 Poor contact in
ECM connector
 Poor contact in
coupling connectorReplace the rear
oxygen sensor.
FU(H4DOTC 2.5)-
38, Rear Oxygen
Sensor.> Step Check Yes No

EN(H4DOTC 2.5)-84
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CONNECT SUBARU SELECT MONITOR OR
THE OBD-II GENERAL SCAN TOOL, AND
READ DATA.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor or the
OBD-II general scan tool to data link connector.
3) Turn the ignition switch to ON and the Sub-
aru Select Monitor or OBD-II general scan tool
switch to ON.
4) Start the engine.
5) Connect the Subaru Select Monitor or
OBD-II general scan tool, and read the mass
air flow sensor voltage.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the voltage 0.2 — 4.7 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air-
flow sensor.
3) Turn the ignition switch to ON.
4) Measure voltage between mass air flow
sensor connector and chassis ground.
Connector & terminal
(B3) No. 3 (+) — Chassis ground (
−):Is the voltage more than 5 V? Repair battery
short circuit in har-
ness between
mass air flow sen-
sor connector and
ECM connector.Go to step 3.
3 CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM connector and mass air flow
sensor connector.
Connector & terminal
(B3) No. 2 — (B136) No. 31:Is the resistance less than 1
Ω?Replace the mass
air flow sensor.
FU(H4DOTC 2.5)-
30, Mass Air Flow
and Intake Air
Temperature Sen-
sor.>Repair open circuit
in harness
between mass air
flow sensor con-
nector and ECM
connector.