2004 SUBARU FORESTER ESP

EN(H4DOTC)-75
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P0121 Throttle/Pedal Position Sensor/
Switch “A” Circuit Range/Perfor-
mance SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE, Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>
P0122 Throttle/Pedal Position Sensor/
Switch “A” Circuit Low Input SENSOR/SWITCH “A” CIRCUIT LOW INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0123 Throttle/Pedal Position Sensor/
Switch “A” Circuit High Input SENSOR/SWITCH “A” CIRCUIT HIGH INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0125 Insufficient Coolant Temperature
For Closed Loop Fuel Control PERATURE FOR CLOSED LOOP FUEL CONTROL, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P0129 Barometric Pressure Too Low LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0131 O
2 Sensor Circuit Low Voltage
(Bank 1 Sensor 1) AGE (BANK 1 SENSOR1), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0132 O
2 Sensor Circuit High Voltage
(Bank 1 Sensor 1) VOLTAGE (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0133 O
2 Sensor Circuit Slow Response
(Bank 1 Sensor 1) RESPONSE (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0134 O
2 Sensor Circuit No Activity
Detected (Bank 1 Sensor 1) ITY DETECTED (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P0137 O
2 Sensor Circuit Low Voltage
(Bank 1 Sensor 2) AGE (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).>
P0139 O
2 Sensor Circuit Slow Response
(Bank 1 Sensor 2) RESPONSE (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).>
P0230 Fuel Pump Primary Circuit Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0244 Turbo/Super Charger Wastegate
Solenoid “A” Range/Performance WASTEGATE SOLENOID “A” RANGE/PERFORMANCE, Diagnostic Proce-
dure 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).>
P0301 Cylinder 1 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0302 Cylinder 2 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0303 Cylinder 3 Misfire Detected DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).> DTC Item NOTE

EN(H4DOTC)-137
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Z: DTC P0133 O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 1 SENSOR 1)
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
WIRING DIAGRAM:
EN-02320
BATTERYMAIN RELAYSBF-5
B47 1 2 3 5 4 6
E
E
B100F2
14LHD
RHD
LHD
RHD
B100
F2
F60
E3
20
3
RHD
RHD6
72
3
33
26
25
ECMB134
: LHD: LHD
B21: RHD: RHD
1
4 2
3
B262
FRONT OXYGEN
(A/F) SENSOR
3412
56
123
4
56
78
9
1011 12
1314 15 16
B21
F60
B47
B262
B134
F2
LHD LHD
1234
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
1234 5678910 11 12 13 14 15 16 17 18 19 20
: LHDE2: RHD

EN(H4DOTC)-147
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AD:DTC P0139 O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 1 SENSOR 2)
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
WIRING DIAGRAM:
MAIN RELAY
B47 1 2 3 5 4 6
E
T5
*1
*2 B18
3
B122
1
3
T6 REAR
OXYGEN SENSOR
A6
A7D31
C35
ECMB135
B136 B :
B134 A :
C :
1
4
B83
B2 D25
B137D :
EN-02321
: LHD
: RHD34
12
56
B21
B134
B135
F60
B83
B47T6
B1361
23456
F2
2143
LHD : 5
RHD : 4
LHD : 1
RHD : 1*1
*2
BATTERY
B100F2 14LHD
RHD
LHD
RHD LHD
RHD
LHD
RHD 4
6
E
B100
F2
F60
E3
20 3
RHD
LHD
RHD
: LHD
B21: RHD
LHD
: LHDE2
: RHD
B18
B122
B137
2345 678911 12 13 14 17 18 19 201101516
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
12345678
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 35
123
4
56
78
9
1011 12
1314 15 16
1234
4
22
T5
B18
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

FU(H4DOTC 2.5)-63
FUEL INJECTION (FUEL SYSTEM)
Fuel System Trouble in General
31.Fuel System Trouble in General
A: INSPECTION
NOTE:
 When the vehicle is left unattended for an extended period of time, water may accumulate in the fuel tank.
To prevent water condensation.
(1) Top off the fuel tank or drain the fuel completely.
(2) Drain the water condensation from the fuel filter.
 Refilling the fuel tank.
Refill the fuel tank while there is still some fuel left in the tank.
 Protecting the fuel system against freezing and water condensation.
(3) Cold areas:
In snow-covered areas, mountainous areas, skiing areas, etc. where ambient temperatures drop below
0°C (32°F) throughout the winter season, use an anti-freeze solution in the cooling system. Refueling will
also complement the effect of anti-freeze solution each time the fuel level drops to about one-half. After
the winter season, drain the water which may have accumulated in the fuel filter and fuel tank in the man-
ner same as that described under “Affected areas” below.
(4) Affected areas:
When the water condensation is notched in the fuel filter, drain the water from both the fuel filter and fuel
tank or use a water removing agent (or anti-freeze solution) in the fuel tank.
 Observe the instructions, notes, etc., indicated on the label affixed to the anti-freeze solution (water remov-
ing agent) container before use.
Trouble and possible cause Corrective action
1. Insufficient fuel supply to the injector
1) Fuel pump will not operate.
❍Defective terminal contact.Inspect connections, especially ground, and tighten
securely.
❍Trouble in electromagnetic or electronic circuit parts. Replace the fuel pump.
2) Lowering of fuel pump function. Replace the fuel pump.
3) Clogged dust or water in the fuel filter. Replace the fuel filter, clean or replace fuel tank.
4) Clogged or bent fuel pipe or hose. Clean, correct or replace the fuel pipe or hose.
5) Air is mixed in the fuel system. Inspect or retighten each connection part.
6) Clogged or bent breather tube or pipe. Clean, correct or replace the air breather tube or pipe.
7) Damaged diaphragm of pressure regulator. Replace.
2. Leakage or blow out fuel
1) Loosened joints of the fuel pipe. Retightening.
2) Cracked fuel pipe, hose and fuel tank. Replace.
3) Defective welding part on the fuel tank. Replace.
4) Defective drain packing of the fuel tank. Replace.
5) Clogged or bent air breather tube or air vent tube.Clean, correct or replace the air breather tube or air vent
tube.
3. Gasoline smell inside of compartment
1)Loose joints at air breather tube, air vent tube and fuel filler
pipe.Retightening.
2) Defective packing air tightness on the fuel saucer. Correct or replace the packing.
3) Cracked fuel separator. Replace the separator.
4) Inoperative fuel pump modulator or circuit. Replace.
4. Defective fuel meter indicator
1) Defective operation of fuel level sensor. Replace.
2) Defective operation of fuel meter. Replace.
5. Noise
1) Large operation noise or vibration of fuel pump. Replace.

4AT-117
AUTOMATIC TRANSMISSION
Front Differential
37.Front Differential
A: REMOVAL
1) Remove the transmission assembly from vehi-
cle. mission Assembly.>
2) Pull out the torque converter clutch assembly.
Clutch Assembly.>
3) Remove the input shaft.
4) Lift-up the lever on rear side of transmission har-
ness connector, and then disconnect it from the
stay.
5) Disconnect the inhibitor switch from the stay.
6) Remove the ATF charger pipe. REMOVAL, Oil Charger Pipe.>
7) Remove the ATF cooler inlet and outlet pipes.
Hose.>
8) Separate the torque converter clutch case and
transmission case. Torque Converter Clutch Case.>
9) Remove the seal pipe.
10) Remove the differential side retainers using
ST.
NOTE:
Hold the differential case assembly by hand to
avoid damaging retainer mounting hole of torque
converter clutch case.
ST 499787000 WRENCH ASSY
11) Remove the differential assembly without dam-
aging installation part of retainer.
B: INSTALLATION
1) Install the differential assembly to torque con-
verter clutch case.
CAUTION:
Do not damage the inside of torque converter
clutch case (especially the mating surface of
differential side retainer).
2) Install the O-ring to left and right differential side
retainer.
3) Install the side retainers using ST. 117, REMOVAL, Front Differential.>
ST 499787000 WRENCH ASSY
4) Adjust the front differential backlash. 4AT-121, ADJUSTMENT, Front Differential.>
5) Install the lock plate.
Tightening torque:
25 N
⋅m (2.5 kgf-m, 18.1 ft-lb)
AT-00114(A) Differential ASSY
(A) Lock plate
AT-00215
(A)
AT-00214
(A)

4AT(H4SO)-20
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Read Diagnostic Trouble Code (DTC)
7. Read Diagnostic Trouble Code (DTC)
A: OPERATION
1. WITHOUT SUBARU SELECT MONITOR
Step Check Yes No
1 PERFORM READ DTC.
1) Warm-up the engine.
2) Turn the ignition switch to OFF.
3) Turn the ignition switch to ON.
4) Start the engine.
5) Drive the vehicle at speeds greater than 20
km/h (12 MPH).
6) Stop the vehicle.
7) The brake pedal depressed and move
select lever to 1 range.
8) Turn the ignition switch to OFF.
9) Turn the ignition switch to ON.
10)Move the select lever “2” range.
11)Move the select lever “1” range.
12)Move the select lever “2” range.
13)Move the select lever “3” range.
14)Move the select lever “D” range.Does the POWER indicator
light blink at 4 Hz intervals?
NOTE: Blinks every 0.125 (1/8)
seconds (until the ignition
switch is turned OFF).Go to step 2.Repair the power
supply and ground
circuit. 4AT(H4SO)-30,
CHECK POWER
SUPPLY AND
GROUND LINE,
INSPECTION,
Power Indicator
Light Display.>
2 CHECK POWER INDICATOR LIGHT.Does the POWER indicator
light blink at 2 Hz intervals?
NOTE: Blinks every 0.25 (1/4)
seconds (until ignition switch is
turned to OFF).The AT system is
normal.Go to step 3.
3 CHECK POWER INDICATOR LIGHT.Is the DTC outputted by the
blink of POWER indicator
light?Inspect the prob-
lem correspond-
ing with DTC.
N
OTE:
Record all DTCs.Go to step 4.
4 CHECK POWER INDICATOR LIGHT.Does the POWER indicator
light remain illuminated?Repair the
POWER indicator
light circuit to 4AT(H4SO)-25,
INSPECTION,
Power Indicator
Light Display.>, or
Inspect inhibitor
switch, wiring,
TCM, etc.Calling up the DTC
again.

4AT(H4SO)-21
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Read Diagnostic Trouble Code (DTC)
 The way of reading Diagnostic Trouble Code (DTC)
The POWER indicator light flashes the code corresponding to faulty part.
The long segment (1.2 sec on) indicates a “ten”, and the short segment (0.2 sec on) signifies a “one”.
2. WITH SUBARU SELECT MONITOR
Refer to Subaru Select Monitor for information about how to obtain and understand DTC. 17, OPERATION, Subaru Select Monitor.>
(1) Normal code (3) DTC 11 and 23 (4) Unit: Seconds
(2) DTC 11
AT-01305
0.25
1.2 1.50.3
0.2
ON
OFF (1)
ON
OFF
1.2 1.50.3
0.2
ON
OFF
1.2
0.3
1.2
0.3 0.3 0.30.2 0.2 0.2
(2)
(3)
(4)

4AT(H4SO)-43
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
9 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM and ECM connector.
Connector & terminal
(B54) No. 3 — (B135) No. 13:Is the resistance less than 1
Ω?Go to step 10.Repair the open
circuit in harness
between TCM and
ECM connector.
10 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM and ECM connector.
Connector & terminal
(B54) No. 2 — (B135) No. 19:Is the resistance less than 1
Ω?Go to step 11.Repair the open
circuit in harness
between TCM and
ECM connector.
11 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 14.Go to step 12.
12 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM, throttle
position sensor and ECM.
2) Turn the ignition switch to ON (engine
OFF).
3) Close the throttle completely.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 3 (+) — Chassis ground (
−):Is the voltage 0.2 — 1.0 V? Go to step 13.Go to step 18.
13 CHECK INPUT SIGNAL FOR TCM.
1) Open the throttle completely.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 3 (+) — Chassis ground (
−):Is the voltage 4.2 — 4.7 V? Go to step 16.Go to step 18.
14 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM, throttle
position sensor and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON (engine
OFF).
4) Turn the Subaru Select Monitor switch to
ON.
5) Throttle fully closed.
6) Read the data of throttle position sensor
using Subaru Select Monitor.
 Throttle position sensor input signal is indi-
cated.Is the value voltage 0.2 — 1.0
V?Go to step 15.Go to step 18.
15 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
Throttle fully open.
N
OTE:
Must be changed correspondingly with the ac-
celerator pedal operation (from “released” to
“depressed” position).Is the value voltage 4.2 — 4.7
V?Go to step 17.Go to step 18. Step Check Yes No