SUBARU FORESTER 2004 Service Repair Manual

4AT(H4DOTC)-105
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
16 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM, accelera-
tor pedal position sensor and ECM.
2) Turn the ignition switch to ON (engine OFF).
3) Open the throttle fully.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B55) No. 19 (+) — Chassis ground (
−):Is the voltage more than 4.6 V? Go to step 18.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 accelerator
pedal position sen-
sor circuit.
17 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM, accelera-
tor pedal position sensor and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON (engine OFF).
4) Turn the Subaru Select Monitor switch to ON.
5) Open the throttle fully.
6) Read the data of accelerator pedal position
sensor using Subaru Select Monitor.
 Accelerator pedal position sensor input sig-
nal is indicated.Is the voltage more than 4.6 V? Go to step 18.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 accelerator
pedal position sen-
sor circuit.
18 CHECK POOR CONTACT.Is there poor contact in sensor
circuit?Repair the poor
contact.Replace the TCM.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-106
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Z: DTC P1714 THROTTLE POSITION SENSOR POWER SUPPLY CIRCUIT
DTC DETECTING CONDITION:
 Power supply circuit of throttle position sensor is open or shorted. (2.0 L model)
 Power supply circuit of accelerator pedal position sensor is open or shorted. (2.5 L model)
TROUBLE SYMPTOM:
 Shift point too high or too low.
 Excessive shift shock.
 Tight corner “braking” phenomenon.

4AT(H4DOTC)-107
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
 LHD model
AT-01851
E13
B122
F60
B134B55 TCM
A:B135 B:ECMB136 C:B137 D:
E3
B100
F2
B200
F74
F61
E2
B200
F74
B100
F2F60
13 14 15 16
12 34
56 78
9
10 11 12
13161415
3
111098
20
1
3
210
19
C18
C16
C35D2D1 D7
B4B12A7 A6B1
EE
12
20
19
18
7
23
16
F61
1
234
56
78
9
1314
15
20
19 1716 10 111218
JOINT CONNECTOR
THROTTLE POSITION SENSOR
F74
34 12 89
10 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
F2
1234 56789
10 11 12 13 14 15 16 17 18 19 20
B134 A:
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
B55
12 7
8956 34
10 11 12
19 20 2113 14 15 16
17 18 22 23 24
B122
12345678
B136
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B137
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
123
E13
B135 B:
567
82 1
94 310
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35

4AT(H4DOTC)-108
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
 RHD model
AT-01852
B55
12 7
8956 34
10 11 12
19 20 2113 14 15 16
17 18 22 23 24
E13
B122
B21
B134B55 TCM
A:B135 B:B137 D: ECMB136 C:
E2B22
E3
B21
13 1415
16
12 34
56 78
9
10
11
12
13161415
3
1
3
210
19
C18
C16
C35D2D1D7
B12B4C19A6 A7B1
EE
1225
1320
20
19
18
B22
1
234
56
78
9
1314
15
20
19 1716 10 111218
JOINT CONNECTOR
THROTTLE
POSITION
SENSOR
B3151
2
6
ACCELERATOR
PEDAL POSITION
SENSOR
123
E13
20
20
20
25
25
25
B315
1
23456
B136
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B137
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B122
12345678
B135 B:
567
82 1
94 310
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B134 A:
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)-109
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND THROTTLE POSITION SENSOR
OR ACCELERATOR PEDAL POSITION SEN-
SOR.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness
between TCM and throttle position sensor or
accelerator pedal position sensor connector.
Connector & terminal
2.0 L model
(B55) No. 10 — (E13) No. 1:
2.5 L model
(B55) No. 10 — (B315) No. 1:Is the resistance less than 1
Ω?Go to step 2.Repair the open cir-
cuit in harness
between TCM and
throttle position
sensor or accelera-
tor pedal position
sensor connector,
and poor contact in
coupling connector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND THROTTLE POSITION SENSOR
OR ACCELERATOR PEDAL POSITION SEN-
SOR.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 10 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
throttle position
sensor or acceler-
ator pedal position
sensor connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Measure the voltage of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 10 (+) — Chassis ground (
−):Is the voltage approx. 5 V? Go to step 4.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 throttle posi-
tion sensor or
accelerator pedal
position sensor cir-
cuit.
4 CHECK POOR CONTACT.Is there poor contact in sensor
circuit?Repair the poor
contact.Replace the TCM.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).>

4AT(H4DOTC)-110
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AA:DTC P1718 CAN COMMUNICATION CIRCUIT
DTC DETECTING CONDITION:
Input signal circuit of TCM is open or shorted.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK DTC.Are multiple DTCs displayed in
the on-board diagnostics test
mode?Go to other DTC. 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 connectors.
Connector & terminal
(B55) No. 3 — (B137) No. 18:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit in harness
between TCM and
ECM or poor con-
tact of connector.
AT-01853
1832612
B55
B137
ECM
B55
TCM
B137
12
7
8956 3410 11 12
19 20 2113 14 15 16
17 1822
23
24
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
TWISTED WIRE

4AT(H4DOTC)-111
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM and ECM connectors.
Connector & terminal
(B55) No. 12 — (B137) No. 26:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit in harness
between TCM and
ECM or poor con-
tact of connector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM and chassis ground connectors.
Connector & terminal
(B55) No. 3 — Chassis ground:
(B55) No. 12 — Chassis ground:Is the resistance more than 1
MΩ?There is failure in
the TCM or ECM.
(Replace and
check again)Repair the short
circuit in harness
between TCM and
ECM. Step Check Yes No

4AT(H4DOTC)-112
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
14.Diagnostic Procedure without Diagnostic Trouble Code (DTC)
A: CHECK FWD SWITCH
DIAGNOSIS:
 The LED does not come on even if FWD switch is ON.
 The FWD signal circuit is open or short.
WIRING DIAGRAM:
 LHD model
AT-01854
BATTERYSBF-4 SBF-1
No.14
IGNITION
SWITCH
FWD
i10
i2
B37
B56TCM
F45
B62
F27
22
9
36
16
35
14
17
COMBINATION
METER
E
E
FWD SWITCH
159i3
B38
123456
78 9 10 1112
13
14
15 16 17
181920
21
2223
24
2526
272829
30
1234
578
910112324
121314
156
16 17 1819
20 2122123 4
57
8
91011
121314
156
16
219
32
B38
1234
5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
2556789
1011121314
1516171819
2021222324
252627282936
3512
34
3031323334
F27
B56
i10B37F45
12
789 56 3
410 11 1219 20 21
29 30 31 13 14 15 1617
27 2818
22 23 24 25 26

4AT(H4DOTC)-113
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
 RHD model
AT-01855
BATTERY
123456
78 9 10 1112
13
14
15 16 17
1819
2021
2223
24
2526
2728
2930
SBF-4 SBF-1
No.14
IGNITION
SWITCH
FWDi10
i3
B38
B56TCM
F45
B62
F27
22
9
36
16
35
14
17
COMBINATION
METER
E
E
FWD SWITCH
1234
5678
910
11
121314
1516 17 1819
20 21221234567812
131415
1617 1891011
1
219
32
i3
1234
5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
56789
1011121314
1516171819
2021222324
252627282936
3512
34
3031323334
F27
i10
i2 B56
F45
1615i2
B37
12
789 56 3
410 11 1219 20 21
29 30 31 13 14 15 1617
27 2818
22 23 24 25 26

4AT(H4DOTC)-114
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK FWD SWITCH.When the fuse is inserted to
FWD switch, does LED light
up?Go to step CHECK
POWER SWITCH.
<Ref. to
4AT(H4DOTC)-
116, CHECK
POWER SWITCH,
Diagnostic Proce-
dure without Diag-
nostic Trouble
Code (DTC).>Go to step 2.
2 CHECK FWD INDICATOR LIGHT.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.Is the FWD indicator light bulb
OK?Go to step 3.Check the combi-
nation meter.
<Ref. to IDI-10,
Combination
Meter Assembly.>
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FWD SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
FWD switch.
3) Measure the resistance of harness
between TCM and FWD switch connector.
Connector & terminal
(B56) No. 17 — (F27) No. 36:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit in harness
between TCM and
FWD switch con-
nector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FWD SWITCH.
Measure the resistance of harness connector
between TCM and body to make sure that cir-
cuit does not short.
Connector & terminal
(B56) No. 17 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
FWD switch con-
nector.
5 CHECK HARNESS CONNECTOR BETWEEN
FWD SWITCH AND CHASSIS GROUND.
Measure the resistance of harness between
FWD switch and chassis ground.
Connector & terminal
(F27) No. 35 — Chassis ground:Is the resistance less than 1
Ω?Go to step 6.Repair the open
circuit in harness
between FWD
switch connector
and chassis
ground.
6 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to FWD switch and
TCM.
3) Turn the ignition switch to ON.
4) Measure the signal voltage for TCM while
installing the fuse to FWD switch connector.
Connector & terminal
(B56) No. 17 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 7.Go to step 11.
7 CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM while
removing the fuse from FWD switch connector.
Connector & terminal
(B56) No. 17 (+) — Chassis ground (
−):Is the voltage more than 10.5
V?Go to step 8.Replace the TCM.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).>
8 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
combination meter.
3) Measure the resistance of harness between
TCM and combination meter connector.
Connector & terminal
(B56) No. 14 — (i10) No. 22:Is the resistance less than 1
Ω?Go to step 9.Repair the open
circuit in harness
between TCM and
combination meter
and poor contact
in coupling con-
nector.