sensor SUBARU FORESTER 2004 Service Repair Manual

4AT(H4SO)-82
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
transmission.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B55) No. 24 — (B11) No. 19:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B54) No. 19 — (B11) No. 20:Is the resistance less than 1
Ω?Go to step 3.Repair the open cir-
cuit in harness
between TCM and
transmission, and
poor contact in cou-
pling connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 24 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B54) No. 19 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
5 CHECK REAR VEHICLE SPEED SENSOR.
Measure the resistance between transmission
connector receptacle’s terminals.
Connector & terminal
(T4) No. 19 — No. 20:Is the resistance 450 — 650
Ω?Go to step 6.Replace the rear
vehicle speed sen-
sor. <Ref. to 4AT-
59, Rear Vehicle
Speed Sensor.>
6 PREPARE OSCILLOSCOPE.Do you have an oscilloscope? Go to step 10.Go to step 7.
7 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 9.Go to step 8.
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up or raise the vehicle and place rigid
rack.
N
OTE:
Raise all wheels off floor.
3) Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
N
OTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control diag-
nosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-23, Clear Memory
Mode.>
4) Measure the voltage between TCM con-
nector terminals.
Connector & terminal
(B55) No. 24 (+) — (B54) No. 19 (
−):Is the voltage more than AC 1
V?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 11.

4AT(H4SO)-83
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
9 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and trans-
mission.
2) Connect the Subaru Select Monitor to data
link connector.
3) Lift-up or raise the vehicle and place rigid
rack.
N
OTE:
Raise all wheels off floor.
4) Turn the ignition switch to ON and turn Sub-
aru Select Monitor switch to ON.
5) Start the engine.
6) Read the data of vehicle speed using Sub-
aru Select Monitor.
 Compare the speedometer with Subaru
Select Monitor indications.
 Vehicle speed is indicated in “km/h” or
“MPH”.
7) Slowly increase the vehicle speed to 60 km/
h (37 MPH).
N
OTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control diag-
nosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-23, Clear Memory
Mode.>Does the speedometer indica-
tion increase as the Subaru
Select Monitor data increases?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 11.
10 CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up or raise the vehicle and place rigid
rack.
NOTE:
Raise all wheels off floor.
3) Set the oscilloscope to TCM connector ter-
minals.
Connector & terminal
Positive probe; (B55) No. 24
Earth lead; (B54) No. 19
4) Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
NOTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control diag-
nosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-23, Clear Memory
Mode.>
5) Measure the signal voltage indicated on
oscilloscope.Is the signal voltage more than
AC 1 V?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 11.
11 CHECK POOR CONTACT.Is there poor contact in rear
vehicle speed sensor circuit?Repair the poor
contact.Replace the TCM.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).> Step Check Yes No

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)-5
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
General Description
3. General Description
A: CAUTION
Supplemental Restraint System “Airbag”
The airbag system wiring harness is routed near
the TCM.
CAUTION:
 All airbag system wiring harness and con-
nectors are colored yellow. Do not use an elec-
trical test equipment on these circuit.
 Be careful not to damage the airbag system
wiring harness when performing diagnostics and
servicing the TCM.
Measurement
When measuring the voltage and resistance of
ECM, TCM or each sensor, use a tapered pin with
diameter of less than 0.64 mm (0.025 in) in order to
avoid poor contact. Do not insert the pin more than
0.65 mm (0.026 in).
B: INSPECTION
1. BATTERY
Measure the battery voltage and specific gravity of
electrolyte.
Standard voltage: 12 V or more
Specific gravity: Above 1.260
2. TRANSMISSION GROUND
Make sure that the ground terminal bolt is tightened
securely.
Chassis side
Tightening torque:
13 N
⋅m (1.3 kgf-m, 9.4 ft-lb)
3. ATF LEVEL
Make sure that ATF level is in the specification. <Ref.
to 4AT-30, INSPECTION, Automatic Transmission
Fluid.>
4. FRONT DIFFERENTIAL OIL LEVEL
Make sure that front differential oil level is in the spec-
ification. <Ref. to 4AT-31, INSPECTION, Differential
Gear Oil.>
AT-00412
(A) Level gauge
(B) “HOT” side
(C) Upper level
(D) Lower level
(E) “COLD” side
(A) Upper level
(B) Lower level
PI-00105
COLD
LFHOT LF
(A)
(C)
(D)
(C)
(D)
(E)
(B)
AT-00317
(A)
(B)
LF

4AT(H4DOTC)-7
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
General Description
C: PREPARATION TOOL
1. SPECIAL TOOL
2. GENERAL TOOL
ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS
24082AA230
(Newly adopted tool)CARTRIDGE Troubleshooting for electrical system.
22771AA030 SUBARU SELECT
MONITOR KITTroubleshooting for electrical system.
 English: 22771AA030 (Without printer)
 German: 22771AA070 (Without printer)
 French: 22771AA080 (Without printer)
 Spanish: 22771AA090 (Without printer)
TOOL NAME REMARKS
Circuit tester Used for measuring resistance, voltage and current.
Oscilloscope Used for measuring sensor.
ST24082AA230
ST22771AA030

4AT(H4DOTC)-10
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Electrical Components Location
2. SENSOR
(1) Throttle position sensor (2.0 L
model)(4) Rear vehicle speed sensor (7) Accelerator pedal position sensor
(2.5 L model)
(5) Torque converter turbine speed
sensor (2) Front vehicle speed sensor
(3) Inhibitor switch (6) ATF temperature sensor
AT-01836
(3) (6)
(5) (1) (2) (4)(7)
(1)
AT-01105
AT-01474
(2)(4)
(3)AT-00330
(5)
AT-00331

4AT(H4DOTC)-13
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Transmission Control Module (TCM) I/O Signal
Accelerator pedal position
sensor (2.5 L model)
B55 19Throttle fully closed. More than 0.2
—
Throttle position sensor (2.0
L model)Throttle fully open. Less than 4.6
Accelerator pedal position
sensor power supply (2.5 L
model)B55 10 Ignition switch ON
(with engine OFF)Approx. 5 —
Throttle position sensor
power supply (2.0 L model)
ATF temperature sensor B55 21ATF temperature 20°C
(68°F)3.5 — 4.3 3.9 k — 4.7 k
ATF temperature 80°C
(176°F)1.5 — 1.9 500 — 600
Rear vehicle speed sensor B55 24Vehicle speed at least
20 km/h (12 MPH)More than 2 (AC range) —
Front vehicle speed sensor B55 6Vehicle stopped. 0
450 — 750
Vehicle speed at least
20 km/h (12 MPH)More than 1 (AC range)
Torque converter turbine
speed sensorB55 7Engine idling after warm-
up. (“D” range)0
450 — 750
Engine idling after warm-
up. (“N” range)More than 1 (AC range)
Vehicle speed output signal B56 1Vehicle speed at least
10 km/h (6 MPH)Less than 1←
→More than 4—
Engine speed signal B55 13Ignition switch ON
(with engine OFF)Less than 1
—
Ignition switch ON
(with engine ON)More than 5
(AC range)
Line pressure linear solenoid B56 20Ignition switch ON
(with engine OFF)
“R” range and throttle fully
closed after warm-up.5 — 7
4.0 — 8.0
Ignition switch ON
(with engine OFF)
“R” range and throttle fully
open after warm-up.3 — 5
Lock-up duty solenoid B56 5When lock up occurs. More than 10.5
2.0 — 4.5
When lock up is released. Less than 1
Transfer duty solenoid B56 4“P” or “N” range Less than 1
2.0 — 4.5
Throttle fully open and with
select lever in 1st gear.More than 10.5
2-4 brake duty solenoid B56 6“P” or “N” range More than 10.5
2.0 — 4.5
2nd or 4th gear Less than 1
High clutch duty solenoid B56 83rd or 4th gear Less than 1
2.0 — 4.5
“P” or “N” range More than 10.5
Low clutch duty solenoid B56 91st or 2nd gear Less than 1
2.0 — 4.5
“P” or “N” range More than 10.5
Low & reverse duty solenoid B56 7“P” or “N” range More than 10.5
2.0 — 4.5
“1” range More than 5
HOLD switch B54 2HOLD switch ON Less than 1
—
HOLD switch OFF More than 10.5 Check with ignition switch ON.
ItemConnector
No.Terminal No. Measuring conditions Voltage (V)Resistance
to chassis
ground (Ω)