2004 SUBARU FORESTER relay

EN(H4SO)-162
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 DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake manifold absolute
pressure sensor signal using Subaru Select
Monitor or OBD-II scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, Subaru Select Monitor.>
 OBD-II scan tool
For detailed operation procedures, refer to the
OBD-II Scan Tool Instruction Manual.Is the value more than 53.3
kPa (400 mmHg, 15.75 inHg)?Make sure that the
EGR valve, mani-
fold absolute pres-
sure sensor and
throttle body are
tightened firmly.Go to step 3.
3 CHECK THE POWER SUPPLY OF EGR
VALVE.
1) Disconnect the connector from EGR valve.
2) Turn the ignition switch to ON.
3) Measure the voltage between EGR valve
and engine ground.
Connector & terminal
(E18) No. 2 — Engine ground:
(E18) No. 5 — Engine ground:Is the voltage more than 10 V? Go to step 4.Repair open circuit
in harness
between main
relay and EGR
valve connector.
4 CHECK EGR VALVE.
Measure the resistance between EGR valve
terminals.
N
OTE:
Make sure there is no foreign material between
EGR valve and valve seat.
Te r m i n a l s
No. 1 — No. 2:
No. 3 — No. 2:
No. 4 — No. 5:
No. 6 — No. 5:Is the resistance 20 — 30 Ω? Go to step 5.Replace the EGR
valve. FU(H4SO)-34,
EGR Valve.>
5 OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Connect the connector to ECM and EGR
valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 15 (+) — Chassis ground (
−):
(B134) No. 16 (+) — Chassis ground (
−):
(B134) No. 17 (+) — Chassis ground (
−):
(B134) No. 18 (+) — Chassis ground (
−):Is the voltage 0 — 10 V? Repair poor con-
tact portion in
ECM connector.Go to step 6.

EN(H4SO)-163
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK HARNESS BETWEEN EGR VALVE
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Detach the connector from EGR valve and
ECM.
3) Measure the resistance of harness
between EGR valve and ECM connector.
Connector & terminal
(B134) No. 18 — (E18) No. 6:
(B134) No. 17 — (E18) No. 1:
(B134) No. 16 — (E18) No. 4:
(B134) No. 15 — (E18) No. 3:Is the resistance less than 1
Ω?Go to step 7.Repair open circuit
in harness
between ECM and
EGR valve con-
nector.
7 CHECK HARNESS BETWEEN EGR VALVE
AND ECM CONNECTOR.
Measure the resistance of harness between
EGR valve and chassis ground.
Connector & terminal
(B134) No. 15 — Chassis ground:
(B134) No. 16 — Chassis ground:
(B134) No. 17 — Chassis ground:
(B134) No. 18 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 8.Repair short circuit
in harness
between main
relay and EGR
valve connector.
8 CHECK POOR CONTACT.
Check that the poor contact of ECM and EGR
valve connector.Is there poor contact of ECM
and EGR valve connector?Repair the poor
contact portion of
ECM and EGR
valve connector.Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a spec-
ified condition at
this time. Step Check Yes No

EN(H4SO)-164
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AN:DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK
1)
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
 Engine stalls
 Idle mixture is out of specifications.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-02391
B18
T6
3412
56
B47F44
12345678
T5B136
B137 B135
BATTERY
REAR
OXYGEN
SENSORFRONT OXYGEN
(A/F) SENSORMAIN RELAYSBF-5
B61 F44
B47
T6
T5
B19B18 1 2 3 5 6
4
E
7
B122
B19B14D15C43
4
2B23C13C22C6C17
1
8
1
B135ECM
B136 B :
C :
B137 D :
5
2
84
3923 20 211011
221617
24
2512136
261915
14
1
7
18
4
1
53
2618 15 167891011
17 19
20121314
567
82 1
94
310
24 22 23 251112131415
26 27
281617181920 21
LHD
LHD
RHD
RHD
4
1
B122
LHDLHD
RHDRHD
4
1 23
3
4
21
1234
3412
B122 : LHD
B122 : RHD
123456781234
B :C :
D :

EN(H4SO)-166
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AO:DTC P0458 EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CON-
TROL VALVE CIRCUIT LOW
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-02392
F44B61
PURGE CONTROL
SOLENOID VALVE
E4
B21
E2
B47
B47
34
12
56
B21
123
4
56
78
9
1011 12
1314 15 16
SBF-5
BATTERY
MAIN RELAY
12
35
46
7
29
21
12
B134ECM
F44
12345678
E4
12
B134
1234567891011121314151617181920212223242526272829303132333435
LHDLHD
RHDRHD

EN(H4SO)-167
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. 29 (+) — Chassis ground (
−):Is the voltage more than 10 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time. Contact
the SUBARU
dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.Go to step 2.
2 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from purge con-
trol solenoid valve and ECM.
3) Measure the resistance of harness
between purge control solenoid valve connec-
tor and engine ground.
Connector & terminal
(E4) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in har-
ness between
ECM and purge
control solenoid
valve connector.
3 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
Measure the resistance of harness between
ECM and purge control solenoid valve of har-
ness connector.
Connector & terminal
(B134) No. 29 — (E4) No. 2:Is the resistance less than 1
Ω?Go to step 4.Repair open circuit
in harness
between ECM and
purge control sole-
noid valve connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and purge
control solenoid
valve connector
 Poor contact in
coupling connector
4 CHECK PURGE CONTROL SOLENOID
VALVE.
1) Remove the purge control solenoid valve.
2) Measure the resistance between purge
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 10 — 100 Ω? Go to step 5.Replace the purge
control solenoid
valve. EC(H4SO)-9,
Purge Control
Solenoid Valve.>
5 CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between purge control
solenoid valve and engine ground.
Connector & terminal
(E4) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 6.Repair open circuit
in harness
between main
relay and purge
control solenoid
valve connector.

EN(H4SO)-169
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AP:DTC P0459 EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CON-
TROL VALVE CIRCUIT HIGH
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-02392
F44B61
PURGE CONTROL
SOLENOID VALVE
E4
B21
E2
B47
B47
34
12
56
B21
123
4
56
78
9
1011 12
1314 15 16
SBF-5
BATTERY
MAIN RELAY
12
35
46
7
29
21
12
B134ECM
F44
12345678
E4
12
B134
1234567891011121314151617181920212223242526272829303132333435
LHDLHD
RHDRHD

EN(H4SO)-182
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02394
No.16
No.17
EE
SBF-4
SBF-1
F17
B134 ECM
14
13F16
F16B72F2 : LHDF27
F17
3412
1
2
SUB FAN
MOTOR
M
1
2
MAIN FAN
MOTOR
M
BATTERY
IGNITION
SWITCHB72
41
21
1234 5678910 11 12 13 14 15 16 17 18 19 20
B134
1234567891011121314151617181920212223242526272829303132333435
3132333435
36
56789
1011121314
1516171819
2021222324
2526272829
1230
34
20A
F27 FAN
MODE
RELAY
AIR CONDITIONING RELAY HOLDER
MAIN
FAN
RELAY-1 SUB
FAN
RELAY
20A
29
25
27
28
30
34
32
317
5
9
2
1
4
3 8 6
B100F2
LHD MODEL : 10
RHD MODEL : 71
LHD MODEL : 11
RHD MODEL : 19
2
*
*
1*
2*
F2 : RHD
12345 678910
11
1219 20 21
13 14 151617
18 22

EN(H4SO)-185
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AW:DTC P0503 VEHICLE SPEED SENSOR CIRCUIT HIGH INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-02395
i10
BATTERY
12
10
ECM COMBINATION
METER
VEHICLE
SPEED
SENSOR
3
12
B17
B137
17
TCMB56
IGNITION
RELAY
No. 5
B225
B21
E216
MTATB17
123
B21
123
4
56
78
9
1011 12
1314 15 16B62
B:
B56
1234
10 11 12
19 20 21135614 1578916 17 18
22 23 24
112
B225
10111213
1415161718
1920212223
2425262728
2930313233
3435363738
12
934
56
78
i10
123456789101112131415161718192021222324252627282930
B37
34 12 8910 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
F45
B137
4
1
53
2618 15 167891011
17 19
20121314
F45
B38i3
B37i2
18
LHD
LHDRHD
RHD
RHD
RHD
LHDLHD
7B38
219
32
1234 5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
C:
*
1*
1 LHD MODEL : 9
RHD MODEL : 37*
2 LHD MODEL : 10
RHD MODEL : 38*
12345678910111213141516
B:C: