2004 SUBARU FORESTER fuel

EN(H4DOTC 2.5)-63
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
F: FUEL INJECTOR CIRCUIT
CAUTION:
 Check or repair only faulty parts.
 After repair or replacement of faulty parts, conduct Clear Memory Mode 42, OPERATION, Clear Memory Mode.> and Inspection Mode TION, Inspection Mode.>.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK OPERATION OF EACH FUEL INJEC-
TOR.
While cranking the engine, check that each
fuel injector emits operating sound. Use a
sound scope or attach a screwdriver to the
injector for this check.Does the fuel pump produce
operating sound?Check the fuel
pressure. ME(H4DOTC)-36,
INSPECTION,
Fuel Pressure.>Go to step 2.
EN-02319
BATTERY
FUEL INJECTORS MAIN RELAY
E#4
1 2
SBF-5
#3
1
2
#2
1 2
#1
1
2
1
9
10
11
12
12
12
7
8956 3410 11 12
19 20 2113 14 1516
17 1822
23
24123
4
56
78
9
1011 12
1314 15 16
6
4
5
3
2
1
B21
B21B136E5
E5
F2
E6
E6
E16
E16
E17
B47
E17
6
5
4
3
B136ECM
B47
34
12
56

EN(H4DOTC 2.5)-64
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
2 CHECK POWER SUPPLY TO EACH FUEL
INJECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
fuel injector terminal and engine ground.
Connector & terminal
#1 (E5) No. 2 (+) — Engine ground (
−):
#2 (E16) No. 2 (+) — Engine ground (
−):
#3 (E6) No. 2 (+) — Engine ground (
−):
#4 (E17) 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
main relay and fuel
injector connector
 Poor contact in
main relay connec-
tor
 Poor contact in
coupling connector
 Poor contact in
fuel injector con-
nector
3 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and fuel injector connector.
Connector & terminal
(B136) No. 6 — (E5) No. 1:
(B136) No. 5 — (E16) No. 1:
(B136) No. 4 — (E6) No. 1:
(B136) No. 3 — (E17) 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 fuel
injector connector
 Poor contact in
coupling connector
4 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
(B136) No. 3 — Chassis ground:
(B136) No. 4 — Chassis ground:
(B136) No. 5 — Chassis ground:
(B136) No. 6 — Chassis ground:Is the resistance less than 1
Ω?Repair ground
short circuit in har-
ness between
ECM and fuel
injector connector.Go to step 5.
5 CHECK EACH FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between each fuel
injector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 5 — 20 Ω? Go to step 6.Replace the faulty
fuel injector.
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Inspection using
“General Diagnos-
tic Table”. EN(H4DOTC 2.5)-
258, INSPEC-
TION, General
Diagnostic Table.> Step Check Yes No

EN(H4DOTC 2.5)-66
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P0137 O2 Sensor Circuit Low Voltage
(Bank 1 Sensor 2) VOLTAGE (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0138 O
2 Sensor Circuit High Voltage
(Bank 1 Sensor 2) VOLTAGE (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0171 System Too Lean (Bank 1) Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0172 System Too Rich (Bank 1) Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0222 Throttle/Pedal Position Sensor/
Switch “B” Circuit Low Input SENSOR/SWITCH “B” CIRCUIT LOW INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0223 Throttle/Pedal Position Sensor/
Switch “B” Circuit High Input SENSOR/SWITCH “B” CIRCUIT HIGH INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0230 Fuel Pump Primary Circuit CUIT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0245 Turbo/Super Charger Wastegate
Solenoid “A” Low WASTEGATE SOLENOID “A” LOW, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0246 Turbo/Super Charger Wastegate
Solenoid “A” High WASTEGATE SOLENOID “A” HIGH, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0327 Knock Sensor 1 Circuit Low Input
(Bank 1 or Single Sensor) LOW INPUT (BANK 1 OR SINGLE SENSOR), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0328 Knock Sensor 1 Circuit High Input
(Bank 1 or Single Sensor) HIGH INPUT (BANK 1 OR SINGLE SENSOR), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0335 Crankshaft Position Sensor “A” Cir-
cuit SENSOR “A” CIRCUIT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0340 Camshaft Position Sensor “A” Cir-
cuit (Bank 1 or Single Sensor) SOR “A” CIRCUIT (BANK 1 OR SINGLE SENSOR), Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P0345 Camshaft Position Sensor “A” Cir-
cuit (Bank 2) SOR “A” CIRCUIT (BANK 2), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0458 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit Low CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT LOW, Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0459 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit High CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT HIGH, Diagnos-
tic Procedure with Diagnostic Trouble Code (DTC).>
P0462 Fuel Level Sensor Circuit Low
Input CUIT LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0463 Fuel Level Sensor Circuit High
Input CUIT HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0502 Vehicle Speed Sensor Circuit Low
Input CIRCUIT LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0503 Vehicle Speed Sensor Intermittent/
Erratic/High INTERMITTENT/ERRATIC/HIGH, Diagnostic Procedure with Diagnostic Trou-
ble Code (DTC).> DTC Item NOTE

EN(H4DOTC 2.5)-115
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
T: DTC P0171 SYSTEM TOO LEAN (BANK 1)
NOTE:
For diagnostic procedure, refer to DTC P0172. RICH (BANK 1), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
U: DTC P0172 SYSTEM TOO RICH (BANK 1)
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
 Erroneous idling
 Engine stalls.
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode OPERATION, Clear Memory Mode.> and Inspection Mode Inspection Mode.>.
Step Check Yes No
1 CHECK EXHAUST SYSTEM.Are there holes or loose bolts
on exhaust system?Repair exhaust
system.Go to step 2.
2 CHECK AIR INTAKE SYSTEM.Are there holes, loose bolts or
disconnection of hose on air
intake system?Repair air intake
system.Go to step 3.
3 CHECK FUEL PRESSURE.
Warning:
 Place “NO FIRE” signs near the working
area.
 Be careful not to spill fuel.
1) Release the fuel pressure.
(1) Disconnect the connector from fuel
pump relay.
(2) Start the engine and run it until it stalls.
(3) After the engine stalls, crank it for five
more seconds.
(4) Turn the ignition switch to OFF.
2) Connect the connector to fuel pump relay.
3) Disconnect the fuel delivery hose from fuel
filter, and connect the fuel pressure gauge.
4) Install the fuel filler cap.
5) Start the engine and idle while gear posi-
tion is neutral.
6) Measure the fuel pressure while discon-
necting pressure regulator vacuum hose from
intake manifold.
Warning:
Release fuel pressure before removing the
fuel pressure gauge.
N
OTE:
If fuel pressure does not increase, squeeze the
fuel return hose 2 to 3 times, then measure fuel
pressure again.Is measured value 284 — 314
kPa (2.9 — 3.2 kg/cm
2, 41 —
46 psi)?Go to step 4.Repair the follow-
ing items.
Fuel pressure is
too high:
 Clogged fuel
return line or
bent hose
Fuel pressure is
too low:
 Improper fuel
pump discharge
 Clogged fuel
supply line

EN(H4DOTC 2.5)-116
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
4 CHECK FUEL PRESSURE.
After connecting the pressure regulator vac-
uum hose, measure fuel pressure.
Warning:
Release fuel pressure before removing the
fuel pressure gauge.
N
OTE:
 If fuel pressure does not increase, squeeze
fuel return hose 2 to 3 times, then measure
fuel pressure again.
 If out of specification as measured at this
step, check or replace pressure regulator and
pressure regulator vacuum hose.Is measured value 206 — 235
kPa (2.1 — 2.4 kg/cm
2, 30 —
34 psi)?Go to step 5.Repair the follow-
ing items.
Fuel pressure is
too high:
 Faulty pres-
sure regulator
 Clogged fuel
return line or
bent hose
Fuel pressure is
too low:
 Faulty pres-
sure regulator
 Improper fuel
pump discharge
 Clogged fuel
supply line
5 CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or the OBD-II general scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 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.Is engine coolant temperature
more than 60°C (140°F)?Go to step 6.Replace the
engine coolant
temperature sen-
sor. FU(H4DOTC 2.5)-
26, Engine Cool-
ant Temperature
Sensor.>
6 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) 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”. 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.Is the measured value within
the following?
Ignition ON: 73.3 — 106.6 kPa
(550 — 800 mmHg, 21.65 —
31.50 inHg) Idling: 24.0 — 41.3
kPa (180 — 310 mmHg, 7.09
— 12.20 inHg)Go to step 7.Replace the mass
air flow and intake
air temperature
sensor. FU(H4DOTC 2.5)-
30, Mass Air Flow
and Intake Air
Temperature Sen-
sor.> 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 OPERATION, Clear Memory Mode.> and Inspection Mode 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.
FU(H4DOTC 2.5)-
44, Fuel Pump
Control Unit.> Step Check Yes No