2004 SUBARU FORESTER check engine

EN(H4SO)-57
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
17.Diagnostics for Engine Starting Failure
A: PROCEDURE
1. Check for fuel amount.
↓
2. Inspection of starter motor circuit. ure.>
↓
3. Inspection of ECM power supply and ground line. ENGINE CONTROL MODULE (ECM), Diagnostics for Engine Starting Failure.>
↓
4. Inspection of ignition control system. Failure.>
↓
5. Inspection of fuel pump circuit.
↓
6. Inspection of fuel injector circuit.

EN(H4SO)-59
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 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 (
−):
N
OTE:
 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 3.Go to step 4.
3 CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the ground cable 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.
4 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 5.Repair open circuit
in harness
between ignition
switch and bat-
tery, and check
fuse SBF No. 4
and SBF No. 1.
5 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 position.
Te r m i n a l s
No. 1 — No. 3:Is the resistance less than 5
Ω?Go to step 6.Replace the igni-
tion switch.
6 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 7.Temporary poor
contact occurs.
Check poor con-
tact in each con-
nectors.
7 CHECK INHIBITOR SWITCH INPUT VOLT-
AGE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from inhibitor
switch.
3) Connect the connector to ignition switch.
4) Measure the input voltage between inhibitor
switch connector terminal and engine ground
while turning the ignition switch to START posi-
tion.
Connector & terminal
(B12) No. 12 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 8.Repair open or
ground short cir-
cuit in harness
between inhibitor
switch and ignition
switch.
N
OTE:
Check security sys-
tem (if equipped).

EN(H4SO)-60
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
8 CHECK INHIBITOR SWITCH.
1) Shift the select lever in the “P” or “N” range.
2) Measure the resistance between inhibitor
switch terminals.
Connector & terminal
(T3) No. 11 — No. 12:Is the resistance less than 1
Ω?Repair open or
ground short cir-
cuit in harness
between inhibitor
switch and starter
motor.Replace inhibitor
switch. 4AT-51, Inhibitor
Switch.> Step Check Yes No

EN(H4SO)-61
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
C: CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MOD-
ULE (ECM)
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-02381
B72
3412
BATTERYIGNITION
SWITCH MAIN RELAY
SBF-4SBF-1
SBF-5
B72B61F44
B2 B1 C12 C16
B21C5
A35
A7
C26
D14B9
C10 C23
No.11B47
E2 B21 1 2 3 5 6 4
ECM
EE
1
7
4
B134
B135
B136 A :
C :
D :B137 B :
C19
8
15
16 14 13
E
3412
56
123
4
56
78
9
1011 12
1314 15 16
B137B135B21B47
MT
MT
F44
B134
12345678
1234567891011121314151617181920212223242526272829303132333435
567
82 1
94
310
24 22 23 251112131415
26 27
281617181920 21
4
1
53
2618 15 167891011
17 19
20121314
B136
5
2
84
3923 20 211011
221617
24
2512136
261915
14
1
7
18
A : C :D :B :
LHDLHD
RHDRHD

EN(H4SO)-62
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. 7 — Chassis ground:
(B134) No. 35 — Chassis ground:
(B135) No. 21 — Chassis ground:
(B136) No. 5 — Chassis ground:
(B136) No. 16 — Chassis ground:
(B136) No. 19 — Chassis ground: (MT
model)
(B136) No. 26 — Chassis ground:
(B137) No. 14 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair open circuit
in harness
between ECM
connector and
engine ground ter-
minal.
3 CHECK INPUT VOLTAGE OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 9 (+) — 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 ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 10 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 5.Repair open or
ground short cir-
cuit of power sup-
ply circuit.
5 CHECK HARNESS BETWEEN ECM AND
MAIN RELAY CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 12 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair ground
short circuit in har-
ness between
ECM connector
and main relay
connector, then
replace the ECM.
6 CHECK OUTPUT VOLTAGE FROM ECM.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 12 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 7.Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>
7 CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.
Connector & terminal
(B47) No. 2 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 8.Repair open circuit
in harness
between ECM
connector and
main relay connec-
tor.

EN(H4SO)-63
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
8 CHECK GROUND CIRCUIT OF MAIN RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between main relay
connector and chassis ground.
Connector & terminal
(B47) No. 1 — Chassis ground:Is the resistance less than 5
Ω?Go to step 9.Repair open circuit
between main
relay and chassis
ground.
9 CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.
Connector & terminal
(B47) No. 5 (+) — Chassis ground (
−):
(B47) No. 6 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 10.Repair open or
ground short cir-
cuit in harness of
power supply cir-
cuit.
10 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. 1 (+) — Chassis ground (
−):
(B135) No. 2 (+) — Chassis ground (
−):
(B136) No. 23 (+) — Chassis ground (
−):Is the voltage more than 10 V? Check ignition
control system.
EN(H4SO)-64,
IGNITION CON-
TROL SYSTEM,
Diagnostics for
Engine Starting
Fa il u r e. >Repair open or
ground short cir-
cuit in harness
between ECM
connector and
main relay connec-
tor. Step Check Yes No

EN(H4SO)-65
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK IGNITION SYSTEM FOR SPARKS.
1) Remove the plug cord cap from each spark
plug.
2) Install the new spark plug on plug cord cap.
CAUTION:
Do not remove the spark plug from engine.
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(H4SO)-67,
FUEL PUMP CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.>Go to step 2.
2 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
(E12) No. 2 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 3.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ignition coil & igni-
tor ASSY, and
main relay connec-
tor
 Poor contact in
coupling connector
 Blown out fuse
3 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
(E12) No. 3 — Engine ground:Is the resistance less than 5
Ω?Go to step 4.Repair 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
4 CHECK IGNITION COIL & IGNITOR ASSY.
1) Remove the spark plug cords.
2) Measure the resistance between spark
plug cord contact portions to check secondary
coil.
Te r m i n a l s
No. 1 — No. 2:
No. 3 — No. 4:Is the resistance 10 — 15 kΩ? Go to step 5.Replace the igni-
tion coil & ignitor
ASSY. IG(H4SO)-8, Igni-
tion Coil & Ignitor
Assembly.>
5 CHECK INPUT SIGNAL FOR IGNITION COIL
& IGNITOR ASSY.
1) Connect the connector to ignition coil &
ignitor ASSY.
2) Check if voltage varies synchronously with
engine speed when cranking, while monitoring
voltage between ignition coil & ignitor ASSY
connector and engine ground.
Connector & terminal
(E12) No. 1 (+) — Engine ground (
−):
(E12) No. 4 (+) — Engine ground (
−):Does the voltage vary more
than 10 V?Go to step 6.Replace the igni-
tion coil & ignitor
ASSY. IG(H4SO)-8, Igni-
tion Coil & Ignitor
Assembly.>

EN(H4SO)-66
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
6 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
(B134) No. 32 — (E12) No. 1:
(B134) No. 32 — (E12) No. 4:Is the resistance less than 1
Ω?Go to step 7.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and ignition
coil & ignitor ASSY
connector.
 Poor contact in
coupling connector
7 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSY CONNEC-
TOR.
Measure the resistance of harness between
ECM and engine ground.
Connector & terminal:
(B134) No. 32 — Engine ground:Is the resistance more than 1
MΩ?Go to step 8.Repair ground
short circuit in har-
ness between
ECM and ignition
coil & ignitor ASSY
connector.
8 CHECK POOR CONTACT.
Check poor contact in ECM connector. Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Check fuel pump
circuit. EN(H4SO)-67,
FUEL PUMP CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.> Step Check Yes No