2004 SUBARU FORESTER automatic transmission

4AT(H4SO)-66
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. 16 — 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 2-4 BRAKE TIMING SOLENOID.
Measure the resistance between transmission
connector terminals.
Connector & terminal
(T4) No. 4 — 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) Lift-up or raise the vehicle and support with
rigid rack.
N
OTE:
Raise all wheels off ground.
3) Start the engine and warm-up the transmis-
sion 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.
4) Move the selector lever to “1” range, and
slowly increase vehicle speed to 10 km/h (6
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. Mode.>
5) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 16 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 5.Go to step 6.
5 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Move the selector lever to “D” range, and
slowly increase vehicle speed to 65 km/h (40
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. Mode.>
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 16 (+) — Chassis ground (
−):Is the voltage more than 9 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 trans-
mission.Go to step 6. Step Check Yes No

4AT(H4SO)-67
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK POOR CONTACT.Is there poor contact in 2-4
brake timing solenoid circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
7 CHECK 2-4 BRAKE TIMING SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Lift-up or raise the vehicle and support with
rigid rack.
N
OTE:
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 2-4 brake timing solenoid.
5) Measure the resistance between 2-4 brake
timing solenoid 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 2-4
brake timing sole-
noid. 71, Shift Sole-
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
8 CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE TIMING SOLENOID AND
TRANSMISSION.
Measure the resistance of harness between 2-
4 brake timing solenoid and transmission con-
nector.
Connector & terminal
(AT8) No. 1 — (T4) No. 4:Is the resistance less than 1
Ω?Go to step 9.Repair the open
circuit in harness
between 2-4 brake
timing solenoid
and transmission
connector.
9 CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE TIMING SOLENOID AND
TRANSMISSION.
Measure the resistance of harness between 2-
4 brake timing solenoid connector and trans-
mission ground.
Connector & terminal
(T4) No. 4 — Transmission ground:Is the resistance more than 1
MΩ?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 2-4
brake timing sole-
noid and transmis-
sion.Repair the short
circuit harness
between 2-4 brake
timing solenoid
and transmission
connector. Step Check Yes No

4AT(H4SO)-68
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
L: DTC 75 LINE PRESSURE DUTY SOLENOID
DTC DETECTING CONDITION:
The output signal circuit of line pressure duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
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 transmis-
sion and TCM.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B54) No. 9 — (B11) No. 5: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 CHASSIS GROUND.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B54) No. 9 — 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 LINE PRESSURE DUTY SOLENOID.
Measure the resistance between transmission
connector receptacle’s terminals.
Te r m i n a l s
(T4) No. 5 — No. 16:Is the resistance between 2.0
and 4.5 Ω?Go to step 4.Go to step 10.
4 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 7.Go to step 5.
AT-00587

9
B54
B11
AT 2
T4 TCM
TRANSMISSION
1234
56789
101112
13
1415 16 17 18
19
20
2122 23
24
B54B11
1
234
56
78
9
1314
15
20
19 1716 10 1112
18
LINE
PRESSURE
DUTY
SOLENOID
5

4AT(H4SO)-69
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Connect all connectors.
2) Start the engine and warm-up the transmis-
sion 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) Turn the ignition switch to ON (engine
OFF).
4) Move the select lever to “N” range.
5) Throttle fully closed.
6) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 9 (+) — Chassis ground (
−):Is the voltage 1.5 — 5.0 V? Go to step 6.Go to step 9.
6 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Throttle fully open and hold it.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 9 (+) — 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
connector in trans-
mission.Go to step 9.
7 CHECK OUTPUT SIGNAL EMITTED FROM
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) Start the engine and turn Subaru Select
Monitor switch to ON.
4) Warm-up the transmission until ATF tem-
perature 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.
5) Stop the engine and turn ignition switch to
ON (engine OFF).
6) Move the select lever to “N” range.
7) Throttle is fully closed.
 Line pressure duty solenoid is indicated in
“%”.
8) Read the data of line pressure duty sole-
noid using Subaru Select Monitor.Is the value 100%? Go to step 8.Go to step 9. Step Check Yes No

4AT(H4SO)-70
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Throttle is fully open.
3) Read the data of line pressure duty sole-
noid using Subaru Select Monitor.Is the value less than 25%? 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 trans-
mission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in line
pressure duty solenoid circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
10 CHECK LINE PRESSURE DUTY SOLENOID
(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 duty solenoid.
4) Measure the resistance between line pres-
sure duty solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the line
pressure duty
solenoid. 4AT-71, Shift Sole-
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE
DUTY SOLENOID.
Measure the resistance of harness between
line pressure duty solenoid and transmission
connector.
Connector & terminal
(T4) No. 5 — (AT2) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between line pres-
sure duty solenoid
and transmission
connector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE
DUTY SOLENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 5 — Transmission ground:Is the resistance more than 1
MΩ?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 line
pressure duty
solenoid and
transmission.Repair the short
circuit in harness
between line pres-
sure duty solenoid
and transmission
connector. Step Check Yes No

4AT(H4SO)-71
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
M: DTC 76 2-4 BRAKE DUTY SOLENOID
DTC DETECTING CONDITION:
The output signal circuit of 2-4 brake duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
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 transmis-
sion and TCM.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B54) No. 18 — (B11) No. 9: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 CHASSIS GROUND.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B54) No. 18 — 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 2-4 BRAKE DUTY SOLENOID.
Measure the resistance between transmission
connector receptacle’s terminals.
Te r m i n a l s
(T4) No. 16 — No. 9:Is the resistance 2.0 — 4.5 Ω? Go to step 4.Go to step 10.
4 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 7.Go to step 5.
AT-00588
18
B54
B11
AT 7
T4 TCM
TRANSMISSION
1234
56789
101112
13
1415 16 17 18
1920
2122 23
24
B54B11
1
234
56
78
9
1314
15
20
19 1716 10 1112
18
2-4
BRAKE DUTY
SOLENOID
9

4AT(H4SO)-72
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Connect all connectors.
2) Start the engine and warm-up the transmis-
sion 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) Turn the ignition switch to ON (engine
OFF).
4) Move the select lever to “N” range.
5) Throttle fully closed.
6) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 18 (+) — Chassis ground (
−):Is the voltage 1.5 — 5.0 V? Go to step 6.Go to step 9.
6 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Throttle fully open and hold it.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 18 (+) — 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
connector in TCM
and transmission.Go to step 9.
7 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Connect all connectors.
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 transmission until ATF tem-
perature is above 80°C (176°F).
NOTE:
If ambient temperature is below 0°C (32°F),
drive the vehicle until ATF reaches its operating
temperature.
5) Stop the engine and turn ignition switch to
ON (engine OFF).
6) Move the select lever to “N” range.
7) Throttle is fully closed.
 2-4 brake duty solenoid is indicated in “%”.
8) Read the data of 2-4 brake duty solenoid
using Subaru Select Monitor.Is the value 100%? Go to step 8.Go to step 9. Step Check Yes No

4AT(H4SO)-73
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Throttle is fully open.
3) Read the data of 2-4 brake duty solenoid
using Subaru Select Monitor.Is the value less than 25%? 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 9.
9 CHECK POOR CONTACT.Is there poor contact in 2-4
brake duty solenoid circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
10 CHECK 2-4 BRAKE DUTY SOLENOID (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 2-4 brake duty solenoid.
4) Measure the resistance between 2-4 brake
duty solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the 2-4
brake duty sole-
noid. 71, Shift Sole-
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure the resistance of harness between 2-
4 brake duty solenoid and transmission con-
nector.
Connector & terminal
(T4) No. 9 — (AT7) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between 2-4 brake
duty solenoid and
transmission con-
nector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 9 — Transmission ground:Is the resistance more than 1
MΩ?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 line
pressure duty
solenoid and
transmission.Repair the short
circuit in harness
between 2-4 brake
duty solenoid and
transmission con-
nector. Step Check Yes No