2004 SUBARU FORESTER automatic transmission

4AT(H4SO)-50
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Measure the resistance between transmis-
sion connector receptacle’s terminals.
Connector & terminal
(T4) No. 14 — No. 15:Is the resistance 450 — 650
Ω?Go to step 2.Replace the tur-
bine speed sensor.
Torque Converter
Turbine Speed
Sensor.>
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B55) No. 8 — (B11) No. 14:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B55) No. 9 — (B11) No. 15:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit in harness
between TCM and
transmission con-
nector, and poor
contact in cou-
pling connector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 9 — 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 HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 8 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair the short
circuit in harness
between TCM and
transmission con-
nector, and poor
contact in cou-
pling connector.
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) Start the engine and move select lever to
“P” or “N” range.
3) Measure the voltage between TCM con-
nector terminals.
Connector & terminal
(B55) No. 8 (+) — No. 9 (
−):Is the voltage more than AC 1
V?Even if the
POWER indicator
lights up, the cir-
cuit has returned
to a normal condi-
tion at this time. A
temporary poor
contact of the con-
nector or harness
may be the cause.
Repair the har-
ness or connector
in TCM and trans-
mission.Go to step 11.

4AT(H4SO)-51
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) Turn the ignition switch to ON and turn Sub-
aru Select Monitor switch to ON.
4) Start the engine.
5) Move the select lever to “P” or “N” range.
6) Read the data of turbine speed using Sub-
aru Select Monitor.
 Compare the tachometer with Subaru Select
Monitor indications.Is the revolution value same as
the tachometer reading shown
on the combination meter?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) Set the oscilloscope to TCM connector ter-
minals.
Connector & terminal
Positive probe; (B55) No. 8
Earth lead; (B55) No. 9
3) Start the engine and move select lever to
“P” or “N” range.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 torque
converter turbine speed sensor
circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4SO)-52
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
F: DTC 38 TORQUE CONTROL SIGNAL
DTC DETECTING CONDITION:
The signal circuit is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
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
(B56) No. 14 — (B136) No. 18:
(B56) No. 5 — (B136) No. 1Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
ECM connector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B56) No. 14 — Chassis ground:
(B56) No. 5 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
ECM connector.
AT-01827
18
114
5
B56
B136
B136ECM
B56
TCM
1234
56789
10 1112
13 14 15 16 17 18
1920451712
89
20
213
1011 12
13
222314 15
242516
2667
18
19
2728
21
2223 24
2930

4AT(H4SO)-53
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
3 CHECK OUTPUT SIGNAL EMITTED FROM
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 terminals.
Connector & terminal
(B56) No. 14 (+) — Chassis ground (
−):
(B56) No. 5 (+) — Chassis ground (
−):Is the voltage more than 4.8 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 ECM.Go to step 4.
4 CHECK POOR CONTACT.Is there poor contact in torque
control signal circuit?Repair the poor
contact.Go to step 5.
5 CHECK GROUND LINE BETWEEN TRANS-
MISSION AND BODY.
Check installing condition of the ground line in
transmission and body.Is there any dirt or rust at the
ground line installing point?Remove dirt and
rust.Go to step 6.
6 CHECK GROUND LINE BETWEEN TRANS-
MISSION AND BODY.
Check installing condition of the ground line in
transmission and body.Is the tightening torque value
13 N⋅m (1.3 kgf-m, 9.4 ft-lb)?Go to step 7.Tighten to the
specified torque.
7 CHECK GROUND LINE INSIDE TRANSMIS-
SION.
1) Drain the ATF and remove oil pan.
2) Check the tightening torque value of ground
line installing bolt.Is the tightening torque value 8
N⋅m (0.8 kgf-m, 5.8 ft-lb)?Go to step 8.Tighten to the
specified torque.
8 CHECK GROUND CIRCUIT OF ECM.
POSITION SENSOR, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>Is there any trouble? Repair the ground
terminal and/or
ground circuit of
ECM.Go to step 9.
9 RECHECK OUTPUT SIGNAL EMITTED
FROM TCM.
Measure the voltage between TCM connector
and chassis ground.
Connector & terminal
(B56) No. 14 (+) — Chassis ground (
−):
(B56) No. 5 (+) — Chassis ground (
−):Is the voltage more than 4 V? Replace the TCM.
Transmission Con-
trol Module
(TCM).>Replace the ECM. Step Check Yes No

4AT(H4SO)-54
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
G: DTC 45 INTAKE MANIFOLD PRESSURE SIGNAL
DTC DETECTING CONDITION:
The input signal circuit of TCM from ECM is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK ENGINE GROUND TERMINALS AND
GROUND CIRCUIT OF ECM
POSITION SENSOR, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>Is there any trouble? Repair the ground
terminal and/or
ground circuit of
ECM.Go to step 2.
2 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
(B54) No. 1 — (B137) No. 2:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit in harness
between TCM and
ECM connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the short
circuit in harness
between TCM and
ECM connector.
4 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 6.Go to step 5.
AT-00582
2
1
B54
B54
B137
B137ECM
TCM
1234
56789
10 1112
13 14 15 16 17 18
19204
5
17
12
89
20
3
1011 12
1314 151667
18
19
21
2223 24

4AT(H4SO)-55
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and ECM.
2) Start the engine, and warm-up the trans-
mission until ATF temperature is above 80°C
(176°F).
N
OTE:
If ambient temperature is below 0°C (32°F),
drive the vehicle until ATF reaches its operating
temperature.
3) Idle the engine.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 1 (+) — Chassis ground (
−):Is the voltage 0.4 — 1.6 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 ECM.Go to step 7.
6 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) Warm-up the engine until engine coolant
temperature is above 80°C (176°F).
5) Idle the engine.
6) Read the data of intake manifold pressure
signal using Subaru Select Monitor.
 Display shows the intake manifold pressure
signal value sent from ECM.Is the voltage 0.4 — 1.6 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 ECM.Go to step 7.
7 CHECK POOR CONTACT.Is there poor contact in intake
manifold pressure signal cir-
cuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4SO)-56
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
H: DTC 71 SHIFT SOLENOID 1
DTC DETECTING CONDITION:
The output signal circuit of shift solenoid 1 is open or shorted.
TROUBLE SYMPTOM:
Does not shift.
WIRING DIAGRAM:
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 shift solenoid 1 connector.
Connector & terminal
(B54) No. 22 — (B11) No. 1:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
AT-00583

22
TRANSMISSION
B54TCM
AT 5
1T4
B11
SHIFT
SOLENOID 1
B54
12
789 56 3410 11 12
19 20 2113 14 15 16 17 18
22
23
24
B11
125678
131415169101112
34
17181920

4AT(H4SO)-57
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 22 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
3 CHECK SHIFT SOLENOID 1.
Measure the resistance between transmission
connector terminals.
Connector & terminal
(T4) No. 1 — No. 16:Is the resistance 10 — 16 Ω? Go to step 4.Go to step 7.
4 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Turn the ignition switch to ON (engine
OFF).
3) Move the select lever to “D” range.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 22 (+) — Chassis ground (
−):Is the voltage more than 9 V? Go to step 5.Go to step 6.
5 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Turn the HOLD mode switch to ON.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 22 (+) — Chassis ground (
−):Is the voltage less than 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
contact in TCM.Go to step 6.
6 CHECK POOR CONTACT.Is there poor contact in shift
solenoid 1 circuit?Repair poor con-
tact.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
7 CHECK SHIFT SOLENOID 1 (IN TRANSMIS-
SION).
1) Remove the transmission connector from
bracket.
2) Lift-up or raise the vehicle and support with
rigid rack.
NOTE:
Raise all wheels off ground.
3) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
4) Remove the oil pan, and disconnect con-
nector from shift solenoid 1.
5) Measure the resistance between shift sole-
noid 1 connector and transmission ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 10 — 16 Ω? Go to step 8.Replace the shift
solenoid 1. to 4AT-71, Shift
Solenoids, Duty
Solenoids and ATF
Temperature Sen-
sor.> Step Check Yes No