2004 SUBARU FORESTER ignition

4AT(H4SO)-93
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SWITCH OPERATION.When the POWER switch is
turned to OFF, does LED light
up?Go to step 5.Go to step 2.
2 CHECK POWER SWITCH OPERATION.When the POWER switch is
turned to ON, does LED light
up?Go to step CHECK
INHIBITOR
SWITCH. 4AT(H4SO)-95,
CHECK INHIBI-
TOR SWITCH,
Diagnostic Proce-
dure without Diag-
nostic Trouble
Code (DTC).>Go to step 3.
3 CHECK POWER INDICATOR LIGHT.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Remove the POWER indicator light bulb
from combination meter.Is the POWER indicator light
bulb OK?Go to step 4.Inspect the combi-
nation meter.
Combination
Meter Assembly.>
4 CHECK POWER SWITCH GROUND LINE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from POWER
switch.
3) Measure the resistance of harness connec-
tor between POWER switch and chassis
ground.
Connector & terminal
LHD model
(R92) No. 4 — Chassis ground:
RHD model
(B133) No. 4 — Chassis ground:Is the resistance less than 1
Ω?Go to step 5.Repair the open
circuit in harness
between POWER
switch and chas-
sis ground.
5 CHECK POWER SWITCH.
1) Turn the POWER switch to ON.
2) Measure the resistance between terminals
of POWER switch.
Te r m i n a l s
No. 5 — No. 4:Is the resistance less than 1
Ω?Go to step 6.Repair the
POWER switch.
6 CHECK POWER SWITCH.
1) Turn the POWER switch to OFF.
2) Measure the resistance between terminals
of POWER switch.
Te r m i n a l s
No. 5 — No. 4:Is the resistance more than 1
MΩ?Go to step 7.Repair the
POWER switch.
7 CHECK HARNESS CONNECTOR BETWEEN
TCM AND POWER SWITCH.
Measure the resistance of harness connector
between TCM and POWER switch.
Connector & terminal
(B55) No. 23 — (B133) No. 3:Is the resistance less than 1
Ω?Go to step 8.Repair the open
circuit in harness
between TCM and
POWER switch
connector.
8 CHECK HARNESS CONNECTOR BETWEEN
TCM AND POWER SWITCH.
Measure the resistance of harness connector
between TCM and chassis ground.
Connector & terminal
(B55) No. 23 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 9.Repair the short
circuit in harness
between TCM and
POWER switch
connector.

4AT(H4SO)-94
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
9 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and
POWER switch.
2) Turn the ignition switch to ON (engine OFF).
3) Measure the signal voltage for TCM while
turning POWER switch to OFF.
Connector & terminal
(B55) No. 23 (+) — Chassis ground (–):Is the voltage more than 10 V? Go to step 10.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
10 CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM while turn-
ing POWER switch to ON.
Connector & terminal
(B55) No. 23 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 11.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
11 CHECK POOR CONTACT.Is there poor contact in
POWER switch circuit?Repair the poor
contact.A temporary poor
contact of the con-
nector or harness
or connector in
POWER switch cir-
cuit. Step Check Yes No

4AT(H4SO)-96
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
 LHD model
AT-00597
BATTERY
SBF-4
COMBINATION
METER IGNITION
SWITCH SBF-1
INHIBITOR SWITCH
E
E
1
3
14
4
5
6
7
10
11
2
3
5
4
1
PRND321
9
8
10
3
11
4
6
53
2
1
8
7
6
5
4
T7
T7B12
B55
B55
B37T3
B12
1234
1234 56
56
12345 7897
78
89
9 10 1112
10 11
10
1112
13
12
1314 15
141516
1617 18
17 18192021
19 20212223 24
22 2324
1 2
i3
B38
TCM
i10
i10
1234
5678
9
10
11
12
No.14
19
2
3
4
5
6
7
ILLUMINATION CONTROL CIRCUIT
3 D N R P
5i2
B37
123456
78 9 10 1112
13
14
15 16 17
1819
2021
2223
24
2526
2728
2930
219
32
1234 5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
B38
6

4AT(H4SO)-97
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
 RHD model
AT-01833
BATTERY
SBF-4
COMBINATION
METER IGNITION
SWITCH SBF-1
INHIBITOR SWITCH
E
E
1
3
14
4
5
6
7
98
7
6
5
4
3
P RND3 2 1
9
8
10
3
11
4
6
53
2
1
8
7
6
5
4
T7
T7B12
B55
B55T3B12
12 34
123456
56 789
789 10 1112
10 1112
13 14 15 16 17 18
192021
2223 24
1 2
TCM
i10
12 34
56 78
9
10
11
12
No.14
ILLUMINATION CONTROL CIRCUIT
3 D N R P
9
3
4
5
6
7 21
123456
78 9 10 1112
13
14
15 16 17
1819
2021
2223
24
2526
2728
2930
i10
219
32
i3
1234
5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
16i3
B38i2
B37
i2
12345 678910
11
1219 20 21
13 14 15 1617
18 22

4AT(H4SO)-99
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
22 CHECK HARNESS CONNECTOR BETWEEN
INHIBITOR SWITCH AND CHASSIS
GROUND.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from inhibitor
switch.
3) Measure the resistance of harness
between inhibitor switch and chassis ground.
Connector & terminal
(T7) No. 5 — Chassis ground:Is the resistance less than 1
Ω?Go to step 23.Repair the open
circuit in harness
between inhibitor
switch connector
and chassis
ground, and poor
contact in cou-
pling connector.
23 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
inhibitor switch.
3) Measure the resistance of harness
between TCM and inhibitor switch connector.
Connector & terminal
(B55) No. 1 — (T7) No. 9:Is the resistance less than 1
Ω?Go to step 24.Repair the open
circuit in harness
between TCM and
inhibitor switch
connector, and
poor contact in
coupling connec-
tor.
24 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor
switch.
3) Turn the ignition switch to ON.
4) Move the select lever to “P” range.
5) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 1 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 25.Go to step 65.
25 CHECK INPUT SIGNAL FOR TCM.
1) Position the select lever to any other than
“P” range.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 1 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 65.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
26 CHECK “P” RANGE INDICATOR LIGHT
BULB.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Remove the “P” range indicator light bulb
from combination meter.Is the “P” range indicator light
bulb OK?Go to step 27.Replace the “P”
range indicator
light bulb. IDI-10, Combina-
tion Meter Assem-
bly.>
27 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Disconnect the connectors from TCM and
combination meter.
2) Measure the resistance of harness
between TCM and combination meter.
Connector & terminal
(B55) No. 1 — (i10) No. 1:Is the resistance more than 1
Ω?Go to step 65.Repair the open cir-
cuit in harness
between TCM con-
nector and combi-
nation meter, and
poor contact in cou-
pling connector.
28 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM,
inhibitor switch and combination meter.
3) Measure the resistance of harness
between TCM and chassis ground.
Connector & terminal
(B55) No. 1 — Chassis ground:Is the resistance less than 1
MΩ?Go to step 29.Repair the ground
short circuit in “P”
range circuit. Step Check Yes No

4AT(H4SO)-100
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
29 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
inhibitor switch.
3) Measure the resistance of harness
between TCM and inhibitor switch connector.
Connector & terminal
(B55) No. 3 — (T7) No. 8:Is the resistance less than 1
Ω?Go to step 30.Repair the open cir-
cuit in harness
between TCM and
inhibitor switch con-
nector, and poor
contact in coupling
connector.
30 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor
switch.
3) Turn the ignition switch to ON.
4) Move the select lever to “R” range.
5) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 3 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 31.Go to step 65.
31 CHECK INPUT SIGNAL FOR TCM.
1) Position the select lever to any other than
“R” range.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 3 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 65.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
32 CHECK “R” RANGE INDICATOR LIGHT
BULB.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Remove the “R” range indicator light bulb
from combination meter.Is “R” range indicator light bulb
OK?Go to step 33.Replace the “R”
range indicator light
bulb. 10, Combination
Meter Assembly.>
33 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Disconnect the connectors from TCM and
combination meter.
2) Measure the resistance of harness
between TCM and combination meter.
Connector & terminal
(B55) No. 3 — (i10) No. 2:Is the resistance less than 1
Ω?Go to step 65.Repair the open
circuit in harness
between TCM con-
nector and combi-
nation meter, and
poor contact in
TCM connector.
34 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM,
inhibitor switch and combination meter.
3) Measure the resistance of harness
between TCM and chassis ground.
Connector & terminal
(B55) No. 3 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 35.Repair the ground
short circuit in “R”
range circuit.
35 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
inhibitor switch.
3) Measure the resistance of harness
between TCM and inhibitor switch connector.
Connector & terminal
(B55) No. 14 — (T7) No. 10:Is the resistance less than 1
Ω?Go to step 36.Repair the open cir-
cuit in harness
between TCM and
inhibitor switch con-
nector, and poor
contact in coupling
connector. Step Check Yes No

4AT(H4SO)-101
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
36 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor
switch.
3) Turn the ignition switch to ON.
4) Move the select lever to “N” range.
5) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 14 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 37.Go to step 65.
37 CHECK INPUT SIGNAL FOR TCM.
1) Position the select lever to any other than
“N” range.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 14 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 65.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
38 CHECK “N” RANGE INDICATOR LIGHT
BULB.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Remove the “N” range indicator light bulb
from combination meter.Is the “N” range indicator light
bulb OK?Go to step 39.Replace the “N”
range indicator
light bulb. IDI-10, Combina-
tion Meter Assem-
bly.>
39 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Disconnect the connectors from TCM and
combination meter.
2) Measure the resistance of harness
between TCM and combination meter.
Connector & terminal
(B55) No. 14 — (i10) No. 3:Is the resistance less than 1
Ω?Go to step 65.Repair the open
circuit in harness
between TCM con-
nector and combi-
nation meter, and
poor contact in
TCM connector.
40 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM,
inhibitor switch and combination meter.
3) Measure the resistance of harness
between TCM and chassis ground.
Connector & terminal
(B55) No. 14 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 41.Repair the ground
short circuit in “N”
range circuit.
41 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
inhibitor switch.
3) Measure the resistance of harness
between TCM and inhibitor switch connector.
Connector & terminal
(B55) No. 4 — (T7) No. 3:Is the resistance less than 1
Ω?Go to step 42.Repair the open cir-
cuit in harness
between TCM and
inhibitor switch con-
nector, and poor
contact in coupling
connector.
42 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor
switch.
3) Turn the ignition switch to ON.
4) Move the select lever to “D” range.
5) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 4 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 43.Go to step 65. Step Check Yes No

4AT(H4SO)-102
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
43 CHECK INPUT SIGNAL FOR TCM.
1) Position select lever to any other than “D”
range.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 4 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 65.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
44 CHECK “D” RANGE INDICATOR LIGHT
BULB.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Remove the “D” range indicator light bulb
from combination meter.Is the “D” range indicator light
bulb OK?Go to step 45.Replace the “D”
range indicator
light bulb. IDI-10, Combina-
tion Meter Assem-
bly.>
45 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Disconnect the connectors from TCM and
combination meter.
2) Measure the resistance of harness
between TCM and combination meter.
Connector & terminal
(B55) No. 4 — (i10) No. 11:Is the resistance less than 1
Ω?Go to step 65.Repair the open
circuit in harness
between TCM con-
nector and combi-
nation meter, and
TCM connector.
46 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM,
inhibitor switch and combination meter.
3) Measure the resistance of harness
between TCM and chassis ground.
Connector & terminal
(B55) No. 4 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 47.Repair the ground
short circuit in “D”
range circuit.
47 CHECK HARNESS CONNECTOR BETWEEN
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
inhibitor switch.
3) Measure the resistance of harness
between TCM and inhibitor switch connector.
Connector & terminal
(B55) No. 5 — (T7) No. 11:Is the resistance less than 1
Ω?Go to step 48.Repair the open cir-
cuit in harness
between TCM and
inhibitor switch con-
nector, and poor
contact in coupling
connector.
48 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor
switch.
3) Turn the ignition switch to ON.
4) Move the select lever to “3” range.
5) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 5 (+) — Chassis ground (–):Is the voltage less than 1 V? Go to step 49.Go to step 65.
49 CHECK INPUT SIGNAL FOR TCM.
1) Position the select lever to any other than
“3” range.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 5 (+) — Chassis ground (–):Is the voltage more than 8 V? Go to step 65.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No