2004 SUBARU FORESTER engine

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.
FU(H4DOTC 2.5)-
44, Fuel Pump
Control Unit.> Step Check Yes No

EN(H4DOTC 2.5)-127
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Y: DTC P0245 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” LOW
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode OPERATION, Clear Memory Mode.> and Inspection Mode Inspection Mode.>.
WIRING DIAGRAM:
EN-02378
MAIN RELAY
B47 1 2 3 5 4 6
BATTERY
E
B47
B134
B127 B134
B127
WASTEGATE
CONTROL SOLENOID
VALVEECM
32 1 2
SBF-5
34 12
56
12
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 2.5)-128
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. 32 (+) — 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.Go to step 2.
2 CHECK HARNESS BETWEEN WASTEGATE
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from wastegate
control solenoid valve and ECM.
3) Measure the resistance in harness
between wastegate control solenoid valve con-
nector and engine ground.
Connector & terminal
(B127) No. 1 — Engine ground:Is the resistance less than 10
Ω?Repair ground
short circuit in har-
ness between
ECM and waste-
gate control sole-
noid valve
connector.Go to step 3.
3 CHECK HARNESS BETWEEN WASTEGATE
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
Measure the resistance of harness between
wastegate control solenoid valve and ECM.
Connector & terminal
(B134) No. 32 — (B127) No. 1:Is the resistance less than 1
Ω?Go to step 4.Repair open circuit
in harness
between ECM and
wastegate control
solenoid valve
connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and waste-
gate control sole-
noid valve
connector
4 CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Remove the wastegate control solenoid
valve.
2) Measure the resistance between wastegate
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 30 — 34 Ω? Go to step 5.Replace the
wastegate control
solenoid valve.
FU(H4DOTC 2.5)-
35, Wastegate
Control Solenoid
Va l ve . >
5 CHECK POWER SUPPLY TO WASTEGATE
CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between wastegate
control solenoid valve and engine ground.
Connector & terminal
(B127) No. 2 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 6.Repair open circuit
in harness
between main
relay and waste-
gate control sole-
noid valve
connector.
6 CHECK POOR CONTACT.
Check poor contact in wastegate control sole-
noid valve connector.Is there poor contact in waste-
gate control solenoid valve
connector?Repair poor con-
tact in wastegate
control solenoid
valve connector.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.

EN(H4DOTC 2.5)-129
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Z: DTC P0246 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” HIGH
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode OPERATION, Clear Memory Mode.> and Inspection Mode Inspection Mode.>.
WIRING DIAGRAM:
EN-02378
MAIN RELAY
B47 1 2 3 5 4 6
BATTERY
E
B47
B134
B127 B134
B127
WASTEGATE
CONTROL SOLENOID
VALVEECM
32 1 2
SBF-5
34 12
56
12
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 2.5)-130
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. 32 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 3.Go to step 2.
2 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>
3 CHECK HARNESS BETWEEN WASTEGATE
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from wastegate
control solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 32 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and waste-
gate control sole-
noid valve
connector. After
repair, replace the
ECM. FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Go to step 4.
4 CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between wastegate
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 1
Ω?Replace the waste-
gate control sole-
noid valve and
ECM. FU(H4DOTC 2.5)-
35, Wastegate
Control Solenoid
Valve.> FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Go to step 5.
5 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>

EN(H4DOTC 2.5)-131
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AA:DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW INPUT (BANK 1 OR SINGLE
SENSOR)
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Poor driving performance
 Knocking occurs.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode OPERATION, Clear Memory Mode.> and Inspection Mode Inspection Mode.>.
WIRING DIAGRAM:
EN-02028
E1E14
B20
2 6
B136 ECM
33 25
E
E14
12
12 34
56
7
89
10
B20
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
KNOCK
SENSOR

EN(H4DOTC 2.5)-132
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN KNOCK SEN-
SOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM har-
ness connector and chassis ground.
Connector & terminal
(B136) No. 25 — Chassis ground:Is the resistance more than
700 kΩ?Go to step 2.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
knock sensor and
ECM connector
 Poor contact in
knock sensor con-
nector
 Poor contact in
coupling connector
2 CHECK KNOCK SENSOR.
1) Disconnect the connector from knock sensor.
2) Measure the resistance between knock
sensor connector terminal and engine ground.
Connector & terminal
(E14) No. 2 — Engine ground:Is the resistance more than
700 kΩ?Go to step 3.Repair the harness
and connector.
NOTE:
In this case repair
the following:
 Poor contact in
knock sensor con-
nector
 Poor contact in
coupling connector
3 CHECK CONDITION OF KNOCK SENSOR
INSTALLATION.Is the knock sensor installation
bolt tightened securely?Replace the knock
sensor. FU(H4DOTC 2.5)-
29, Knock Sen-
sor.>Tighten knock sen-
sor installation bolt
securely.