SUBARU FORESTER 2004 Service Repair Manual

4AT(H4SO)-112
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
No shift occurs from 3rd to 4th gear.TCM
 Shift solenoid 1
 ATF temperature sensor
 Control valve
2-4 brake
Engine brake is not effected when select lever is in “3” range. Inhibitor switch
TCM
 Throttle position sensor
 Control valve
Engine brake is not effected when select lever is in “3” or “2”
range. Control valve
Engine brake is not effected when select lever is in “1” range. Control valve
 Low & reverse brake
Shift characteristics are erroneous. Inhibitor switch
TCM
 Front vehicle speed sensor
 Rear vehicle speed sensor
 Throttle position sensor
 Control valve
 Ground earth
No lock-up occurs.TCM
 Throttle position sensor
 ATF temperature sensor
 Control valve
 Lock-up facing
 Engine speed signal
Parking brake is not effected.  Select cable
 Select lever
 Parking mechanism Shift lever cannot be moved or is hard to move from “P” range.
ATF spurts out.  ATF level too high
Differential oil spurts out.  Differential gear oil too high
Differential oil level changes excessively. Seal pipe
 Double oil seal
Odor is produced from ATF supply pipe.High clutch
2-4 brake
 Low & reverse clutch
 Reverse clutch
 Lock-up facing
 ATF deterioration
Shock occurs from 1st to 2nd gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
2-4 brake
 ATF deterioration
 Engine performance
 2-4 brake timing solenoid
Slippage occurs from 1st to 2nd gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
2-4 brake
 2-4 brake timing solenoid
High clutch Symptom Problem parts

4AT(H4SO)-113
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
Shock occurs from 2nd to 3rd gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
High clutch
2-4 brake
 ATF deterioration
 Engine performance
 2-4 brake timing solenoid
Slippage occurs from 2nd to 3rd gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
High clutch
2-4 brake
 2-4 brake timing solenoid
Shock occurs from 3rd to 4th gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
 2-4 brake timing solenoid
2-4 brake
 ATF deterioration
 Engine performance
 Low clutch timing solenoid
 Low clutch
Slippage occurs from 3rd to 4th gear.TCM
 Throttle position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
2-4 brake
 2-4 brake timing solenoid
Shock occurs when select lever is moved from “3” to “2” range.TCM
 Throttle position sensor
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
 2-4 brake duty solenoid
2-4 brake
 ATF deterioration
 2-4 brake timing solenoid
Shock occurs when select lever is moved from “D” to “1” range.TCM
 Throttle position sensor
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
 ATF deterioration
 2-4 brake duty solenoid
 2-4 brake timing solenoid
 Low clutch timing solenoid Symptom Problem parts

4AT(H4SO)-114
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
Shock occurs when select lever is moved from “2” to “1” range.TCM
 Throttle position sensor
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
 Low & reverse clutch
 ATF deterioration
 2-4 brake duty solenoid
 2-4 brake timing solenoid
 Low clutch timing solenoid
Shock occurs when accelerator pedal is released at medium
speeds.TCM
 Throttle position sensor
 ATF temperature sensor
 Line pressure duty solenoid
 Control valve
 Lock-up damper
 Engine performance
 2-4 brake duty solenoid
 2-4 brake timing solenoid
 Low clutch timing solenoid
Vibration occurs during straight-forward operation.TCM
 Lock-up duty solenoid
 Lock-up facing
 Lock-up damper
HOLD switch
Vibration occurs during turns (tight corner “braking” phenomenon).TCM
 Front vehicle speed sensor
 Rear vehicle speed sensor
 Throttle position sensor
 ATF temperature sensor
 Transfer clutch
Transfer valve
 Transfer duty solenoid
 ATF deterioration
Harness
HOLD switch
Front wheel slippage occurs during standing starts.TCM
 Front vehicle speed sensor
FWD switch
 Throttle position sensor
 ATF temperature sensor
 Control valve
 Transfer clutch
Transfer valve
 Transfer pipe
 Transfer duty solenoid
Vehicle is not set in FWD mode.TCM
FWD switch
 Transfer clutch
Transfer valve
 Transfer duty solenoid
Select lever is hard to move. Select cable
 Select lever
 Detente spring
 Manual plate
Select lever is too hard to move (unreasonable resistance). Detente spring
 Manual plate Symptom Problem parts

4AT(H4SO)-115
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
Select lever slips out of operation during acceleration or while
driving on rough terrain. Select cable
 Select lever
 Detente spring
 Manual plate Symptom Problem parts

4AT(H4SO)-116
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic

FUJI HEAVY INDUSTRIES LTD. G8080GE5
2004 FORESTER SERVICE MANUAL QUICK REFERENCE INDEX
TRANSMISSION SECTION
This service manual has been prepared
to provide SUBARU service personnel
with the necessary information and data
for the correct maintenance and repair
of SUBARU vehicles.
This manual includes the procedures
for maintenance, disassembling, reas-
sembling, inspection and adjustment of
components and diagnostics for guid-
ance of experienced mechanics.
Please peruse and utilize this manual
fully to ensure complete repair work for
satisfying our customers by keeping
their vehicle in optimum condition.
When replacement of parts during
repair work is needed, be sure to use
SUBARU genuine parts.
All information, illustration and specifi-
cations contained in this manual are
based on the latest product information
available at the time of publication
approval.CONTROL SYSTEM CS
AUTOMATIC TRANSMISSION 4AT
AUTOMATIC TRANSMISSION
(DIAGNOSTIC)4AT(H4SO)
AUTOMATIC TRANSMISSION
(DIAGNOSTIC)4AT(H4DOTC)
AUTOMATIC TRANSMISSION
(DIAGNOSTIC)4AT(H4DOTC 2.5)
MANUAL TRANSMISSION AND
DIFFERENTIAL5MT
CLUTCH SYSTEM CL

AUTOMATIC TRANSMISSION
(DIAGNOSTIC)
4AT(H4DOTC)
Page
1. Basic Diagnostic Procedure ........................................................................2
2. Check List for Interview ...............................................................................4
3. General Description ....................................................................................5
4. Electrical Components Location..................................................................8
5. Transmission Control Module (TCM) I/O Signal .......................................12
6. Subaru Select Monitor...............................................................................15
7. Read Diagnostic Trouble Code (DTC) ......................................................18
8. Inspection Mode ........................................................................................19
9. Clear Memory Mode..................................................................................20
10. Power Indicator Light Display....................................................................21
11. Diagnostic Procedure for Subaru Select Monitor Communication ............27
12. List of Diagnostic Trouble Code (DTC) .....................................................30
13. Diagnostic Procedure with Diagnostic Trouble Code (DTC) .....................33
14. Diagnostic Procedure without Diagnostic Trouble Code (DTC) ..............112
15. Symptom Related Diagnostic ..................................................................126

4AT(H4DOTC)-2
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Basic Diagnostic Procedure
1. Basic Diagnostic Procedure
A: PROCEDURE
Step Check Yes No
1 CHECK PRE-INSPECTION.
1) Ask the customer when and how trouble
occurred using interview checklist. <Ref. to
4AT(H4DOTC)-4, Check List for Interview.>
2) Before performing the diagnosis, inspect
following items which might influence the AT
problems.
 General inspection <Ref. to 4AT(H4DOTC)-
5, INSPECTION, General Description.>
 Disconnection of harness connector
 Visually check the damage of harness
 Oil leak
 Stall speed test <Ref. to 4AT-33, Stall Test.>
 Line pressure test <Ref. to 4AT-36, Line
Pressure Test.>
 Transfer clutch pressure test <Ref. to 4AT-
38, Transfer Clutch Pressure Test.>
 Time lag test <Ref. to 4AT-35, Time Lag
Te s t . >
 Road test <Ref. to 4AT-32, Road Test.>
 Inhibitor switch <Ref. to 4AT-51, Inhibitor
Switch.>Is the unit that might influence
AT problem normal?Go to step 2.Repair or replace
each item.
2 CHECK POWER INDICATOR LIGHT.
Turn the ignition switch to ON.Does the POWER indicator
light illuminate?Go to step 4.Go to step 3.
3 CHECK POWER INDICATOR LIGHT.
1) Turn the ignition switch to OFF.
2) Repair the POWER indicator light circuit or
power supply and ground line circuit.
<Ref. to 4AT(H4DOTC)-22, INSPECTION,
Power Indicator Light Display.>
3) Turn the ignition switch to ON.Is the POWER indicator light
flashing?Go to step 4.Go to step 5.
4 READ OF DTC.
Calling up the DTC.
N
OTE:
If the communication function of Subaru Select
Monitor cannot be executed normally, check the
communication circuit. <Ref. to 4AT(H4DOTC)-
27, COMMUNICATION FOR INITIALIZING IM-
POSSIBLE, Diagnostic Procedure for Subaru
Select Monitor Communication.>Is the DTC displayed? Go to step 6.
NOTE:
Record all DTC.Go to step 5.
5 PERFORM THE GENERAL DIAGNOSTICS.
1) Inspect using “Diagnostics Procedure with-
out DTC”. <Ref. to 4AT(H4DOTC)-112, Diag-
nostic Procedure without Diagnostic Trouble
Code (DTC).>
2) Inspect using “Symptom Related Diagnos-
tic”. <Ref. to 4AT(H4DOTC)-126, Symptom
Related Diagnostic.>
3) Perform the clear memory mode.
4) Perform the inspection mode. <Ref. to
4AT(H4DOTC)-19, Inspection Mode.>
5) Calling up the DTC.Is the DTC displayed? Go to step 6.Complete the
diagnosis.

4AT(H4DOTC)-3
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Basic Diagnostic Procedure
6 PERFORM THE DIAGNOSIS.
1) Inspect using “Diagnostics Procedure with
DTC”. <Ref. to 4AT(H4DOTC)-33, Diagnostic
Procedure with Diagnostic Trouble Code
(DTC).>
N
OTE:
For DTC table, refer to “List of DTC”. <Ref. to
4AT(H4DOTC)-30, List of Diagnostic Trouble
Code (DTC).>
2) Repair the trouble cause.
3) Perform the clear memory mode.
4) Perform the inspection mode. <Ref. to
4AT(H4DOTC)-19, Inspection Mode.>
5) Calling up the DTC.Is DTC displayed? Inspect using
“Diagnostics pro-
cedure with Diag-
nostic Trouble code
(DTC)”. <Ref. to
4AT(H4DOTC)-33,
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC).>Complete the
diagnosis. Step Check Yes No

4AT(H4DOTC)-4
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Check List for Interview
2. Check List for Interview
A: CHECK
Check the following items when problem has occurred.
NOTE:
Use copies of this page for interviewing customers.
Customer’s name
Date of purchase
Date of repair
Trans. model TRANSMISSION VIN
Odometer readingkm/h or miles
Frequency❏ Continuous ❏ Intermittent ( times a day)
Weather❏ Fine ❏ Cloudy ❏ Rainy ❏ Snowy
❏ Va r i o u s / O t h e r s
()
Place❏ High ❏ Suburbs ❏ Inner city ❏ Uphill ❏ Rough road
❏ Others
()
Outdoor temperature❏ Hot ❏ War m ❏ Cool ❏ Cold
Vehicle speedkm/h (MPH)
AT warning light (POWER indicator
light)❏ Continuously blinking❏ Not blinking
Select lever position❏ P ❏ R ❏ N ❏ D ❏ 3 ❏ 2 ❏ 1
Driving condition❏ Not affected
❏ At racing
❏ While decelerating❏ At starting
❏ While accelerating
❏ While turning (❏ RH / ❏ LH)❏ While idling
❏ While cruising
POWER switch❏ ON / ❏ OFF
HOLD switch❏ ON / ❏ OFF
Symptoms❏ No up-shift
❏ No down-shift
❏ No kick down
❏ Vehicle does not move (❏ Any position ❏ Particular position)
❏ Lock-up malfunction
❏ Noise or vibration
❏ Shift shock or slip
❏ Select lever does not move
❏ Others
()