2004 SUBARU FORESTER oil pressure

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. 4AT(H4DOTC)-4, Check List for Interview.>
2) Before performing the diagnosis, inspect
following items which might influence the AT
problems.
 General inspection 5, INSPECTION, General Description.>
 Disconnection of harness connector
 Visually check the damage of harness
 Oil leak
 Stall speed test
 Line pressure test Pressure Test.>
 Transfer clutch pressure test 38, Transfer Clutch Pressure Test.>
 Time lag test Te s t . >
 Road test
 Inhibitor switch 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.
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. 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”. nostic Procedure without Diagnostic Trouble
Code (DTC).>
2) Inspect using “Symptom Related Diagnos-
tic”. Related Diagnostic.>
3) Perform the clear memory mode.
4) Perform the inspection mode. 4AT(H4DOTC)-19, Inspection Mode.>
5) Calling up the DTC.Is the DTC displayed? Go to step 6.Complete the
diagnosis.

4AT(H4DOTC)-71
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
1) Fully open the throttle.
2) Shift the select lever to “R” range. (engine
OFF)
3) Read the data of line pressure linear sole-
noid.Is the value 20 — 40%? Even if the POWER
indicator light was
blinking, the circuit
has returned to a
normal condition at
this time. A tempo-
rary poor contact of
the connector or
harness may be the
cause. Repair the
harness or connec-
tor in transmission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in line
pressure linear solenoid cir-
cuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
10 CHECK LINE PRESSURE LINEAR SOLE-
NOID (IN TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the oil pan, and disconnect con-
nector from line pressure linear solenoid.
4) Measure the resistance between line pres-
sure linear solenoid connector and transmis-
sion ground.
Connector & terminal
(AT11) No. 2 — No. 4:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the con-
trol valve body.
Control Valve
Body.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE LIN-
EAR SOLENOID.
Measure the resistance of harness between
line pressure linear solenoid and transmission
connector.
Connector & terminal
(T4) No. 2 — (AT11) No. 4:
(T4) No. 1 — (AT11) No. 2:Is the resistance less than 1
Ω?Go to step 12.Repair the open cir-
cuit in harness
between line pres-
sure linear solenoid
and transmission
connector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE LIN-
EAR SOLENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 1 — Transmission ground:
(T4) No. 2 — Transmission ground:Is the resistance more than 1
MΩ?Even if the POWER
indicator light was
blinking, the circuit
has returned to a
normal condition at
this time. A tempo-
rary poor contact of
the connector or
harness may be the
cause. Repair the
harness or connec-
tor in line pressure
linear solenoid and
transmission.Repair the short
circuit in harness
between line pres-
sure linear sole-
noid and
transmission con-
nector. Step Check Yes No

4AT(H4DOTC)-126
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. Select cable
 Inhibitor switch
TCM
 Low clutch
Shock occurs when select lever is shifted from “N” to “D” range. Accelerator pedal position sensor
 ATF temperature sensor
 Line pressure linear solenoid
 Low clutch duty solenoid
 Low clutch
TCM
Harness
 Control valve
 ATF deterioration
Excessive time lag occurs when select lever is shifted from “N”
to “D” range. Control valve
 Low clutch
 Line pressure duty solenoid
 Seal ring
 Front gasket of transmission case
Shock occurs when select lever is shifted from “N” to “R” range. Accelerator pedal position sensor
 ATF temperature sensor
 Line pressure linear solenoid
TCM
Harness
 Control valve
 ATF deterioration

4AT(H4DOTC)-127
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
Excessive time lag occurs when select lever is shifted from “N”
to “R” range. Control valve
 Low & reverse clutch
 Reverse clutch
 Line pressure linear solenoid
 Seal ring
 Front gasket of transmission case
Vehicle does not start in any shift range (engine stalls). Parking brake mechanism
 Planetary gear
Vehicle does not start in any shift range (engine revving up). Strainer
 Line pressure linear 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 of transmission case
Vehicle does not start in “R” range only (engine revving up). Select cable
 Select lever
 Line pressure linear solenoid
 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
 ATF deterioration
 Front gasket of 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 Symptom Problem parts

4AT(H4DOTC)-128
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Symptom Related Diagnostic
No shift occurs from 1st to 2nd gear.TCM
 Rear vehicle speed sensor
 Front vehicle speed sensor
 Throttle position sensor
 Control valve
2-4 brake
No shift occurs from 2nd to 3rd gear.TCM
 Control valve
High clutch
No shift occurs from 3rd to 4th gear.TCM
 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
 Torque converter turbine speed sensor
 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
 Torque converter turbine speed sensor
 Accelerator pedal position sensor
 2-4 brake duty solenoid
 ATF temperature sensor
 Line pressure linear solenoid
 Control valve
2-4 brake
 ATF deterioration
 Engine performance
 Low & reverse duty solenoid Symptom Problem parts

CL-42
CLUTCH SYSTEM
General Diagnostic Table
12.General Diagnostic Table
A: INSPECTION
1. CLUTCH
Symptom Possible cause Corrective
1. Clutch slippage.
It is hard to perceive clutch slippage in
the early stage, but pay attention to the
following symptoms
 Engine speed up when shifting.
 High speed driving is impossible; espe-
cially rapid acceleration impossible and
vehicle speed does not increase in pro-
portion to an increase in engine speed.
 Power falls, particularly when ascend-
ing a slope, and there is a smell of burn-
ing of the clutch facing.
 Method of testing: Put the vehicle in
stationary condition with parking brake
fully applied. Disengage the clutch and
shift the transmission gear into the first.
Gradually allow the clutch to engage
while gradually increasing the engine
speed. The clutch function is satisfactory
if the engine stalls. However, the clutch is
slipping if the vehicle does not start off
and the engine does not stall.(a) Clutch facing smeared by oil Replace.
(b) Worn clutch facing Replace.
(c) Deteriorated diaphragm spring Replace.
(d) Distorted pressure plate or flywheel Replace.
(e) Defective release bearing holder Replace.
2. Clutch drags.
As a symptom of this trouble, a harsh
scratching noise develops and control
becomes quite difficult when shifting
gears. The symptom becomes more
apparent when shifting into the first gear.
However, because much trouble of this
sort is due to defective synchronization
mechanism, carry out the test as
described after.
 Method of testing: DIAGNOSTIC DIAGRAM OF CLUTCH
DRAG, INSPECTION, General Diagnos-
tic Table.>
It may be judged as insufficient disen-
gagement of clutch if any noise occurs
during this test.(a) Worn or rusty clutch disc hub spline Replace the clutch disc.
(b) Excessive deflection of clutch disc
facingReplace.
(c) Malfunction of crankshaft pilot bearing Replace.
(d) Cracked clutch disc facing Replace.
(e) Stuck clutch disc (smeared by oil or
water)Replace.
3. Clutch chatters.
Clutch chattering is an unpleasant vibra-
tion to the whole body when the vehicle is
just started with clutch partially engaged.(a) Adhesion of oil on the facing Replace the clutch disc.
(b) Weak or broken torsion spring Replace the clutch disc.
(c) Defective facing contact or excessive
disc wornReplace the clutch disc defection.
(d) Warped pressure plate or flywheel Replace.
(e) Loose disc rivets Replace the clutch disc.
(f) Loose engine mounting Retighten or replace the mounting.
(g) Improper adjustment of pitching stop-
perAdjustment.