SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC)-208
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 2.Go to step 3.
2 CHECK SPEEDOMETER OPERATION IN
COMBINATION METER.Does speedometer operate
normally?Go to step 3.Check the speed-
ometer. <Ref. to
IDI-13, Speedom-
eter.>
3 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the combi-
nation meter.
3) Measure the resistance between ECM and
combination meter connector.
Connector & terminal
(B134) No. 1 — (i11) No. 2:Is the resistance less than 10
Ω?Repair the poor
contact in ECM
connector.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and combi-
nation meter con-
nector
 Poor contact in
ECM connector.
 Poor contact in
combination meter
connector
 Poor contact in
coupling connector

EN(H4DOTC)-209
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BG:DTC P0506 IDLE CONTROL SYSTEM RPM LOWER THAN EXPECTED
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
 Engine is difficult to start.
 Engine does not start.
 Erroneous idling
 Engine stalls.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
WIRING DIAGRAM:
EN-02339
BATTERY MAIN RELAY
EE
7 6
4
5
3
2
1RHD
RHDLHD LHD
27
IDLE
AIR CONTROL
SOLENOID
VALVE
1
3
E7
B47
B4734
12
56
F44
12345678
B134
F44B61
B134
ECM
2
1
RHD
RHD
LHD LHD
B100
F2
F60B21
E3
15
SBF-5
: LHD : RHD
F60
B22 : LHD
: RHD
E7
123
125678
131415169101112
34
17181920
123
4
56
78
9
1011 12
1314 15 16
F74
F61
B21 : LHD
: RHDRHD RHD
E3
B2212
LHD
LHD
12
E2
F61
F74
B200
34
128910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
F2
1234 5678910 11 12 13 14 15 16 17 18 19 20
E2
: LHD : RHD
20
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31

EN(H4DOTC)-210
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)”. <Ref. to
EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0506.Go to step 2.
2 CHECK IDLE AIR CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve
from the throttle body. <Ref. to FU(H4DOTC)-
37, REMOVAL, Idle Air Control Solenoid
Va l ve. >
3) Using an air gun, force air into the idle air
control solenoid valve by-pass air inlet.Confirm
that forced air subsequently escapes from both
main air passage and assist air passage.Does air flow out? Go to step 3.Replace the idle
air control solenoid
valve. <Ref. to
FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>
After replace, Go
to step 3.
3 CHECK IDLE AIR CONTROL SOLENOID
VALVE DUTY RATIO.
1) Turn the ignition switch to ON.
2) Start the engine, and warm-up the engine.
3) Turn all accessory switches to OFF.
4) Read the data of idle air control solenoid
duty ratio 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”. <Ref. to EN(H4DOTC)-
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 duty ratio more than 60% Go to step 4.END.
4 CHECK BY-PASS AIR LINE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve
from the throttle body. <Ref. to FU(H4DOTC)-
37, REMOVAL, Idle Air Control Solenoid
Va l ve. >
3) Remove the throttle body from the intake
manifold. <Ref. to FU(H4DOTC)-13,
REMOVAL, Throttle Body.>
4) Using an air gun, force air into the solenoid
valve installation area and throttle valve inte-
rior.Confirm that forced air subsequently
escapes from both these areas.Does air flow out? Replace the idle
air control solenoid
valve. <Ref. to
FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>Replace the throt-
tle body. <Ref. to
FU(H4DOTC)-13,
Throttle Body.>

EN(H4DOTC)-211
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BH:DTC P0507 IDLE CONTROL SYSTEM RPM HIGHER THAN EXPECTED
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
Engine keeps running at higher revolution than specified idling revolution
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
WIRING DIAGRAM:
EN-02339
BATTERY MAIN RELAY
EE
7 6
4
5
3
2
1RHD
RHDLHD LHD
27
IDLE
AIR CONTROL
SOLENOID
VALVE
1
3
E7
B47
B4734
12
56
F44
12345678
B134
F44B61
B134
ECM
2
1
RHD
RHD
LHD LHD
B100
F2
F60B21
E3
15
SBF-5
: LHD : RHD
F60
B22 : LHD
: RHD
E7
123
125678
131415169101112
34
17181920
123
4
56
78
9
1011 12
1314 15 16
F74
F61
B21 : LHD
: RHDRHD RHD
E3
B2212
LHD
LHD
12
E2
F61
F74
B200
34
128910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
F2
1234 5678910 11 12 13 14 15 16 17 18 19 20
E2
: LHD : RHD
20
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31

EN(H4DOTC)-212
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)”. <Ref. to
EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0507.Go to step 2.
2 CHECK THROTTLE CABLE.Does the throttle cable have
play for adjustment?Go to step 3.Adjust throttle
cable. <Ref. to
SP(H4SO)-9,
INSTALLATION,
Accelerator Con-
trol Cable.>
3 CHECK AIR INTAKE SYSTEM.
1) Turn the ignition switch to ON.
2) Start and idle the engine.
3) Check the following items:
 Loose installation of intake manifold, idle air
control solenoid valve and throttle body
 Cracks of intake manifold gasket, idle air
control solenoid valve gasket and throttle body
gasket
 Disconnections of vacuum hosesIs there any fault in air intake
system?Repair air suction
and leaks.Replace the idle
air control solenoid
valve. <Ref. to
FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>

EN(H4DOTC)-213
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BI: DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Engine stalls.
 Engine breathing
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
WIRING DIAGRAM:
EN-02339
BATTERY MAIN RELAY
EE
7 6
4
5
3
2
1RHD
RHDLHD LHD
27
IDLE
AIR CONTROL
SOLENOID
VALVE
1
3
E7
B47
B4734
12
56
F44
12345678
B134
F44B61
B134
ECM
2
1
RHD
RHD
LHD LHD
B100
F2
F60B21
E3
15
SBF-5
: LHD : RHD
F60
B22 : LHD
: RHD
E7
123
125678
131415169101112
34
17181920
123
4
56
78
9
1011 12
1314 15 16
F74
F61
B21 : LHD
: RHDRHD RHD
E3
B2212
LHD
LHD
12
E2
F61
F74
B200
34
128910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
F2
1234 5678910 11 12 13 14 15 16 17 18 19 20
E2
: LHD : RHD
20
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31

EN(H4DOTC)-214
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 27 (+) — Chassis ground (
−):Is the voltage more than 3 V? Repair the poor
contact in ECM
connector.Go to step 2.
2 CHECK POWER SUPPLY TO IDLE AIR CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from idle air con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between idle air con-
trol solenoid valve and engine ground.
Connector & terminal
(E7) 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
idle air control
solenoid valve and
main relay connec-
tor
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and idle air control solenoid
valve connector.
Connector & terminal
(B134) No. 27 — (E7) 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 idle air
control solenoid
valve connector
 Poor contact in
coupling connector
4 CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B134) No. 10 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair ground
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connector.
5 CHECK GROUND CIRCUIT OF IDLE AIR
CONTROL SOLENOID VALVE.
Measure the resistance of harness between
idle air control solenoid valve connector and
engine ground.
Connector & terminal
(E7) No. 3 — Engine ground:Is the resistance less than 5
Ω?Go to step 6.Repair open circuit
in harness
between idle air
control solenoid
valve connector
and engine ground
cable.
6 CHECK POOR CONTACT.
Check poor contact in ECM and idle air control
solenoid valve connectors. Is there poor contact in ECM
and idle air control solenoid
valve connectors?Repair poor con-
tact in ECM and
idle air control
solenoid valve
connectors.Replace the idle
air control solenoid
valve. <Ref. to
FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>

EN(H4DOTC)-215
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BJ:DTC P0509 IDLE CONTROL SYSTEM CIRCUIT HIGH
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Engine stalls.
 Engine breathing
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
WIRING DIAGRAM:
EN-02339
BATTERY MAIN RELAY
EE
7 6
4
5
3
2
1RHD
RHDLHD LHD
27
IDLE
AIR CONTROL
SOLENOID
VALVE
1
3
E7
B47
B4734
12
56
F44
12345678
B134
F44B61
B134
ECM
2
1
RHD
RHD
LHD LHD
B100
F2
F60B21
E3
15
SBF-5
: LHD : RHD
F60
B22 : LHD
: RHD
E7
123
125678
131415169101112
34
17181920
123
4
56
78
9
1011 12
1314 15 16
F74
F61
B21 : LHD
: RHDRHD RHD
E3
B2212
LHD
LHD
12
E2
F61
F74
B200
34
128910 11
12 13 14 15 16 17 18 19 20 21 22 23 2456 7
F2
1234 5678910 11 12 13 14 15 16 17 18 19 20
E2
: LHD : RHD
20
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31

EN(H4DOTC)-216
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK THROTTLE CABLE.Does the throttle cable have
play for adjustment?Go to step 2.Adjust throttle
cable. <Ref. to
SP(H4SO)-9,
Accelerator Con-
trol Cable.>
2 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 27 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 3.Go to step 4.
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from idle air con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 27 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connec-
tor.After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Replace the idle
air control solenoid
valve and ECM.
<Ref. to
FU(H4DOTC)-37,
Idle Air Control
Solenoid Valve.>
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 27 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair battery
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connec-
tor.After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

EN(H4DOTC)-217
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BK:DTC P0512 STARTER REQUEST CIRCUIT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
Failure of engine to start
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
WIRING DIAGRAM:
EN-02311
BATTERY
INHIBITOR SWITCH
IGNITION
SWITCH
STARTER
MOTOR
SBF-4SBF-1
B72
B72
B14
B137
ECM
EE
1
3
D8
3412
B137
T3B12MT
AT
AT
MT
1112712
PR
N
D3
21
T7
B12
123
8
9
10
4
11
1256
7
T7
123
8910411 1256
7567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31