2004 SUBARU FORESTER engine

4AT(H4SO)-95
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
G: CHECK INHIBITOR SWITCH
DETECTING CONDITION:
The input signal circuit of inhibitor switch is open or shorted.
TROUBLE SYMPTOM:
 Shift characteristics are erroneous.
 Engine brake is not effected when selector lever is in “3” range.
 Engine brake is not effected when selector lever is in “2” range.
 Engine brake is not effected when selector lever is in “1” range.

4AT(H4SO)-109
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
9 CHECK HARNESS CONNECTOR BETWEEN
TCM AND HOLD SWITCH.
Measure the resistance of harness connector
between TCM and chassis ground to make
sure that circuit does not short.
Connector & terminal
(B55) No. 16 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 10.Repair the short
circuit in harness
between TCM and
HOLD switch con-
nector.
10 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and HOLD
switch.
2) Turn the ignition switch to ON (engine OFF).
3) Measure the signal voltage for TCM while
turning HOLD switch to OFF.
Connector & terminal
(B55) No. 16 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 11.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
11 CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM while turn-
ing HOLD switch to ON.
Connector & terminal
(B55) No. 16 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 12.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
12 CHECK POOR CONTACT.Is there poor contact in HOLD
switch circuit?Repair the poor
contact.A temporary poor
contact of the con-
nector or harness or
connector in HOLD
switch circuit. Step Check Yes No

4AT(H4SO)-110
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
15.Symptom Related Diagnostic
A: INSPECTION
Symptom Problem parts
Starter does not rotate when select lever is in “P” or “N” range;
starter rotates when select lever is in “R”, “D”, “3” or “2” range. Inhibitor switch
 Select cable
 Select lever
 Starter motor and harness
Abnormal noise when select lever is in “P” or “N” range. Strainer
 Transfer duty solenoid
 Oil pump
Drive plate
 ATF level too high or too low
Hissing noise occurs during standing start. Strainer
 ATF level too high or too low
Noise occurs while driving in “D1”.  Final gear
 Planetary gear
 Reduction gear
 Differential gear oil level too high or too low Noise occurs while driving in “D2”.
Noise occurs while driving in “D3”. Final gear
 Low & reverse brake
 Reduction gear
 Differential gear oil level too high or too low
Noise occurs while driving in “D4”. Final gear
 Low & reverse brake
 Planetary gear
 Reduction gear
 Differential gear oil level too high or too low
Engine stalls while shifting from “1” range to another. Control valve
 Lock-up damper
 Engine performance
 Input shaft
Vehicle moves when select lever is in “N” range.  Low clutch
Shock occurs when select lever is moved from “N” to “D” range.TCM
Harness
 Control valve
 ATF deterioration
Excessive time lag occurs when select lever is moved from “N”
to “D” range. Control valve
 Low clutch
 Line pressure duty solenoid
 Seal ring
 Front gasket transmission case
Shock occurs when select lever is moved from “N” to “R” range.TCM
Harness
 Control valve
 ATF deterioration
Excessive time lag occurs when select lever is moved from “N”
to “R” range. Control valve
 Low & reverse clutch
 Reverse clutch
 Line pressure duty solenoid
 Seal ring
 Front gasket transmission case
Vehicle does not start in any shift range (engine stalls). Parking brake mechanism
 Planetary gear

4AT(H4SO)-111
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
Vehicle does not start in any shift range (engine revving up). Strainer
 Line pressure duty solenoid
 Control valve
 Drive pinion
 Hypoid gear
Axle shaft
 Differential gear
 Oil pump
 Input shaft
 Output shaft
 Planetary gear
Drive plate
 ATF level too low
 Front gasket transmission case
Vehicle does not start in “R” range only (engine revving up). Select cable
 Select lever
 Control valve
 Low & reverse clutch
 Reverse clutch
Vehicle does not start in “R” range only (engine stalls). Low clutch
2-4 brake
 Planetary gear
 Parking brake mechanism
Vehicle does not start in “D”, “3” range only (engine revving up). Low clutch
 One-way clutch
Vehicle does not start in “D”, “3” or “2” range only (engine rev-
ving up). Low clutch
Vehicle does not start in “D”, “3” or “2” range only (engine stalls).  Reverse clutch
Vehicle starts in “R” range only (engine revving up).  Control valve
Acceleration during standing starts is poor (high stall rpm). Control valve
 Low clutch
 Reverse clutch
 ATF level too low
 Front gasket transmission case
 Differential gear oil level too high or too low
Acceleration during standing starts is poor (low stall rpm). Oil pump
 Torque converter one-way clutch
 Engine performance
Acceleration is poor when select lever is in “D”, “3” or “2” range
(normal stall rpm).TCM
 Control valve
High clutch
2-4 brake
 Planetary gear
Acceleration is poor when select lever is in “R” (normal stall rpm). Control valve
High clutch
2-4 brake
 Planetary gear
No shift occurs from 1st to 2nd gear.TCM
 Rear vehicle speed sensor
 Front vehicle speed sensor
 Throttle position sensor
 Shift solenoid 1
 Control valve
2-4 brake
No shift occurs from 2nd to 3rd gear.TCM
 Control valve
High clutch
 Shift solenoid 2 Symptom Problem parts

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(H4DOTC)-6
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
General Description
5. OPERATION OF SELECT LEVER
Make sure there is no abnormal noise, dragging or
contact pattern in each select lever range.
WARNING:
Stop the engine while checking operation of se-
lect lever.
6. POWER SWITCH
Make sure that the POWER indicator light in com-
bination meter comes on, when turning the POW-
ER switch to ON.
7. HOLD SWITCH
Make sure that the HOLD indicator light in combina-
tion meter comes on, when turning the HOLD switch
to ON.
AT-00413
P
R
N
D
3
2
1
AT-00319
AT-00320