SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC 2.5)-117
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR
1) Start and warm-up the engine until engine
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all accessory switches to OFF.
5) Open the hood.
6) Measure the ambient temperature.
7) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or the 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”. <Ref. to EN(H4DOTC
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.Subtract the ambient tempera-
ture from intake air tempera-
ture, and is the value −10 —
50°C (14 — 122°F)?Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.Check mass air
flow and intake air
temperature sen-
sor. <Ref. to
FU(H4DOTC 2.5)-
30, Mass Air Flow
and Intake Air
Temperature Sen-
sor.> Step Check Yes No

EN(H4DOTC 2.5)-118
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
V: DTC P0222 THROTTLE/PEDAL POSITION SENSOR/SWITCH “B” CIRCUIT
LOW INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Poor driving performance
 Engine stalls.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.

EN(H4DOTC 2.5)-119
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02364
B317
34
12
B22
125678
131415169101112
34
17181920
B21
123
4
56
78
9
1011 12
1314 15 16
B83
1
23456
B135
567
82 1
94 3
10
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B:
B35D6
B135 B: C:
D4 D3
C18
B1 C35
D1 B4
D2
SBF-5
2
1
3
4
E
E57
3
6 4
1
2 2
3
15
16
E
5
EE
B137 D:ECM B309
B136
B122
1
E2 B21
E3 B22 B317
E56B47 35
2 1
4 3
D5C16C29
19122018
MAIN RELAYBATTERY
ELECTRONIC
THROTTLE
CONTROL ELECTRONIC
THROTTLE
CONTROL
RELAY
B83
B122
123456783412
56
B47
B137
567
82 1
94 3
10
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B136
56
782 1
94 3
10
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B309
34
12
E57

EN(H4DOTC 2.5)-120
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and terminal.
Connector & terminal
(B136) No. 29 (+) — (B136) No. 35 (
−):
3) Check the voltage change by shaking the
harness and connector of ECM, engine har-
ness connector and electronic throttle control
connector.Is the voltage more than 0.8 V? Go to step 2.Go to step 3.
2 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact? Repair the poor
contact.Temporary poor
contact occurred,
but it is normal at
present.
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 16 — (E57) No. 5:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit of harness
connector.
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 29 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the chas-
sis short circuit of
harness.
5 CHECK SENSOR POWER SUPPLY.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage 4.5 — 5.5 V? Go to step 6.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
6 CHECK SHORT CIRCUIT INSIDE THE ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 — Engine ground:Is the resistance more than 10
Ω?Repair poor con-
tact of electronic
throttle control
connector.
Replace the elec-
tronic throttle con-
trol if defective.Repair the poor
contact in ECM
connector. Replace
the ECM if defec-
tive. <Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>

EN(H4DOTC 2.5)-121
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
W: DTC P0223 THROTTLE/PEDAL POSITION SENSOR/SWITCH “B” CIRCUIT
HIGH INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Poor driving performance
 Engine stalls.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.

EN(H4DOTC 2.5)-122
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
Step Check Yes No
1 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of sub throttle sensor signal
using Subaru Select Monitor.
3) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage less than 4.73
V?Go to step 2.Go to step 3.
EN-02364
B317
34
12
B22
125678
131415169101112
34
17181920
B21
123
4
56
78
9
1011 12
1314 15 16
B83
1
23456
B135
567
82 1
94 3
10
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B:
B35D6
B135 B: C:
D4 D3
C18
B1 C35
D1 B4
D2
SBF-5
2
1
3
4
E
E57
3
6 4
1
2 2
3
15
16
E
5
EE
B137 D:ECM B309
B136
B122
1
E2 B21
E3 B22 B317
E56B47 35
2 1
4 3
D5C16C29
19122018
MAIN RELAYBATTERY
ELECTRONIC
THROTTLE
CONTROL ELECTRONIC
THROTTLE
CONTROL
RELAY
B83
B122
123456783412
56
B47
B137
567
82 1
94 3
10
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B136
56
782 1
94 3
10
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B309
34
12
E57

EN(H4DOTC 2.5)-123
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact in con-
nector between ECM and elec-
tronic throttle control?Repair the poor
contact.Temporary poor
contact occurred,
but it is normal at
present.
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 29 — (E57) No. 4:
(B136) No. 35 — (E57) No. 3:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit of harness
connector.
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 3 — Engine ground:Is the resistance less than 5
Ω?Go to step 5.Repair the poor
contact in ECM
connector. Replace
the ECM if defec-
tive. <Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>
5 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage more than 10 V? Go to step 6.Repair battery
short circuit in har-
ness between
ECM connector
and electronic
throttle control
connector.
6 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 (+) — Engine ground (
−):
2) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage less than 10 V? Go to step 7.Repair battery
short circuit in har-
ness between
ECM connector
and electronic
throttle control
connector.
7 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between connector
terminals.
Connector & terminal
(B136) No. 29 — (B136) No. 16:Is the resistance more than 1
MΩ?Repair the poor
contact. Replace
the electronic
throttle control if
defective.Sensor power sup-
ply circuit may be
shorted. Step Check Yes No

EN(H4DOTC 2.5)-124
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
X: DTC P0230 FUEL PUMP PRIMARY CIRCUIT
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
EN-02358
R15
E
E M
R122: B135 B
: B137
D
R58
B97 B97
3412
B98 R1
R15
R57
567
82 1
94 310
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
R122
3
4 12
5891067
FUEL PUMP
CONTROL MODULE
FUEL PUMPECMBATTERY
B72SBF-1
SBF-4
D28
B27
E
98 10
7
6 1
4 1
415
14
1 4
5
IGNITION SWITCH
B46 FUEL PUMP
RELAY
2
1 4
3SBF-5
No.118B98
R2
12345678219
32
1234
5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
: B135
B: B137
D
B72
3412
R58
23
56 1
4

EN(H4DOTC 2.5)-125
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY CIRCUIT TO FUEL
PUMP CONTROL UNIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel pump
control unit.
3) Turn the ignition switch to ON.
4) Measure the voltage between fuel pump
control unit and chassis ground.
Connector & terminal
(R122) No. 10 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 2.Repair the power
supply circuit.
N
OTE:
In this case repair
the following:
 Open or ground
short circuit in har-
ness between fuel
pump relay and
fuel pump control
unit.
 Poor contact in
fuel pump control
unit connector.
 Poor contact in
fuel pump relay
connector.
2 CHECK GROUND CIRCUIT OF FUEL PUMP
CONTROL UNIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between fuel pump control unit and chassis
ground.
Connector & terminal
(R122) No. 5 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair the harness
and connector.
NOTE:
In this case repair
the following:
 Open circuit
between fuel pump
control unit and
chassis ground.
 Poor contact in
fuel pump control
unit connector.
3 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND FUEL PUMP CONNEC-
TOR.
1) Disconnect the connector from fuel pump.
2) Measure the resistance of harness
between fuel pump control unit and fuel pump
connector.
Connector & terminal
(R122) No. 6 — (R58) No. 4:
(R122) No. 7 — (R58) No. 1:Is the resistance less than 1
Ω?Go to step 4.Repair open circuit
between fuel pump
control unit and
fuel pump.
4 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND FUEL PUMP CONNEC-
TOR.
Measure the resistance of harness between
fuel pump control unit and chassis ground.
Connector & terminal
(R122) No. 6 — Chassis ground:
(R122) No. 7 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair ground
short circuit
between fuel pump
control unit and
fuel pump.
5 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance in harness
between fuel pump control unit and ECM con-
nector.
Connector & terminal
(R122) No. 8 — (B137) No. 28:
(R122) No. 9 — (B135) No. 27: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 circuit
between fuel pump
control unit and
ECM.
 Poor contact in
fuel pump control
unit and ECM con-
nector

EN(H4DOTC 2.5)-126
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND ECM CONNECTOR.
Measure the resistance of harness between
fuel pump control unit and chassis ground.
Connector & terminal
(R122) No. 8 — Chassis ground:
(R122) No. 9 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 7.Repair the ground
short circuit
between fuel pump
control unit and
ECM.
7 CHECK POOR CONTACT.
Check poor contact in ECM and fuel pump
control unit connector.Is there poor contact in ECM
and fuel pump control unit con-
nector?Repair the poor
contact in ECM
and fuel pump
control unit.Go to step 8.
8 CHECK EXPERIENCE OF RUNNING OUT OF
FUEL.Did the vehicle experience run-
ning out of fuel?Finish the diagno-
sis.
N
OTE:
DTC record may
be conducted as a
result of fuel pump
idling while running
out of gas.Replace the fuel
pump control unit.
<Ref. to
FU(H4DOTC 2.5)-
44, Fuel Pump
Control Unit.> Step Check Yes No