2004 SUBARU FORESTER automatic transmission

4AT(H4DOTC)-53
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
stop light switch.
3) Measure the resistance of harness
between TCM and stop light switch.
Connector & terminal
(B55) No. 20 — (B65) No. 3:Is the resistance less than 1
Ω?Go to step 4.Repair the open
harness between
TCM and stop light
switch.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND STOP LIGHT SWITCH.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 20 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
stop light switch.
5 INSPECT POOR CONTACT.Is there poor contact in the
stop light switch input signal
circuit?Repair poor con-
tact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-54
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
F: DTC P0720 OUTPUT SPEED SENSOR CIRCUIT
DTC DETECTING CONDITION:
 The vehicle speed signal is abnormal.
 The circuit in combination meter is faulty.
 The harness connector between TCM and vehicle speed sensor is in short or open.
TROUBLE SYMPTOM:
 Erroneous idling.
 Engine stalls.
 Poor driving performance.
WIRING DIAGRAM:
AT-01845
18 14
B11
B299
T4
B6
B15C1
B11
12 34
5678
9
13 14 15
20 19 1716 10 11 1218
i10
B37
i2
B38
i3
TCM
B55 B:
B56 C:
18
12
1234567813 14 15 16 17 18 1911 101225 26 27 28 29 30 31
921203223 2224
i3
B56
12 78 956 34
10 11 12 19 20 21
29 30 31 13 14 15 16 17
27 2818
22 23 24 25 26
C:
FRONT
VEHICLE SPEED
SENSOR CONBINATION
METER
SPEEDOMETER
: RHD MODEL SHIELD
JOINT
CONNECTOR
LHD
RHD
RHD
: LHD MODEL
LHD RHD
7
834
LHD
i10
123456789101112131415161718192021222324252627282930
B:B55
12 7
8956 34
10 11 12
19 20 2113 14 15 16
17 18 22 23 24
B37
34 12 89
10 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
B299
12345678

4AT(H4DOTC)-55
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. 6 — (B11) No. 14: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
(B55) No. 15 — (B11) No. 18:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit in harness
between TCM and
transmission con-
nector, and poor
contact in cou-
pling connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B55) No. 6 — 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 transmission connector.
Connector & terminal
(B55) No. 15 — 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, and poor
contact in cou-
pling connector.
5 CHECK FRONT VEHICLE SPEED SENSOR.
Measure the resistance between transmission
connector receptacle’s terminals.
Connector & terminal
(T4) No. 14 — No. 18:Is the resistance 450 — 650
Ω?Go to step 6.Replace the front
vehicle speed sen-
sor. 55, Front Vehicle
Speed Sensor.>
6 PREPARE OSCILLOSCOPE.Do you have an oscilloscope? Go to step 9.Go to step 7.
7 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 10.Go to step 8.
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect all connectors.
2) Lift-up the vehicle and place rigid racks.
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 clear-
ance procedure of on-board diagnostics system.

4) Measure the voltage between TCM con-
nector terminals.
Connector & terminal
(B55) No. 6 (+) — No. 15 (
−):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
or harness may be
the cause. Repair
the harness or
connector in the
front vehicle speed
sensor circuit.Go to step 11.

4AT(H4DOTC)-56
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
9 CHECK FRONT VEHICLE SPEED SENSOR
USING OSCILLOSCOPE.
1) Connect all connectors.
2) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
3) Set the oscilloscope to TCM connector ter-
minals.
Connector & terminal
Positive probe; (B55) No. 6:
Earth lead; (B55) No. 15:
4) Start the engine, and drive the wheels
slowly.
N
OTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunctions. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostic sys-
tem.
5) Measure the signal voltage indicated on
oscilloscope.Is the voltage more than AC 4
V?Even if the POWER
indicator light was
blinking, the circuit
has returned to a
normal condition at
this time. A tempo-
rary poor contact or
harness may be the
cause. Repair the
harness or connec-
tor in front vehicle
speed sensor cir-
cuit.Go to step 11.
10 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect all connectors.
2) Connect the Subaru Select Monitor to data
link connector.
3) Lift-up the vehicle and place rigid racks.
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 clear-
ance procedure of on-board diagnostics system.
Does the speedometer indica-
tion increase as Subaru Select
Monitor data increases?Even if the POWER
indicator light was
blinking, the circuit
has returned to a
normal condition at
this time. A tempo-
rary poor connec-
tor or harness may
be the cause.
Repair the harness
or connector in
front vehicle speed
sensor circuit.Go to step 11.
11 CHECK POOR CONTACT.Is there poor contact in front
vehicle speed sensor circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-57
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
G: DTC P0724 TORQUE CONVERTER/BRAKE SWITCH “B” CIRCUIT HIGH
DTC DETECTING CONDITION:
Stop light switch malfunction or open input signal circuit.
TROUBLE SYMPTOM:
Gear is not shifted down when climbing hill.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK TCM INPUT SIGNAL.
1) Disconnect the harness connector from
TCM.
2) Measure the voltage of harness between
TCM and stop light switch.
Connector & terminal
(B55) No. 20 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 2.Go to step 4.
AT-01844
B55
B65
E
2 3
SBF-1
SBF-2
NO.16
20
B55
B65
TCM
12 7
8956 34
10 11 12
19 20 2113 14 15 16
17 18 22 23 24
1234
BATTERY
STOP LIGHT
SWITCH
TO STOP LIGHT

4AT(H4DOTC)-58
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light
switch.
3) Measure the resistance between stop light
switch connector.
Connector & terminal
No. 2 — No. 3:Is the resistance more than 1
MΩ?Go to step 3.Replace the stop
light switch.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND STOP LIGHT SWITCH.
1) Turn the ignition switch to ON.
2) Measure the voltage of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 20 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 4.Repair the short in
power supply cir-
cuit to harness
between TCM and
stop light switch.
4 INSPECT POOR CONTACT.Is there poor contact in the
stop light switch input signal
circuit?Repair poor con-
tact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-59
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
H: DTC P0725 ENGINE SPEED INPUT CIRCUIT
DTC DETECTING CONDITION:
Engine speed input signal circuit is open or shorted.
TROUBLE SYMPTOM:
 No lock-up (after engine warm-up).
 POWER indicator light remains on when vehicle speed is “0”.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
ECM.
3) Measure the resistance of harness
between TCM and ECM connector.
Connector & terminal
(B55) No. 13 — (B134) No. 23:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
ECM connector.
AT-01846
B55
23
13
B134
ECM
B55
TCM
B134
12
7
8956 3410 11 12
19 20 2113 14 15 16
17 1822
23
24
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

4AT(H4DOTC)-60
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 13 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
ECM connector.
3 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 5.Go to step 4.
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and ECM.
2) Turn the ignition switch to ON (engine OFF).
3) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B55) No. 13 (+) — Chassis ground (
−):Is the voltage less than 1 V? 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 of TCM and
ECM.Go to step 6.
5 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine and turn Subaru Select
Monitor switch to ON.
4) Idle the engine.
5) Read the data of engine speed using Sub-
aru Select Monitor.
 Display shows the engine speed signal value
sent from ECM.Is the revolution value same as
tachometer reading shown on
combination meter?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 of TCM and
ECM.Go to step 6.
6 CHECK POOR CONTACT.Is there poor contact in engine
speed signal circuit?Repair the poor
contact.Go to step 7.
7 CONFIRM DTC P0725.
Replace the ECM with a new one. Does the DTC appear again,
after memory has been
cleared?Replace the TCM.
Transmission Con-
trol Module
(TCM).>Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).> Step Check Yes No