2004 SUBARU FORESTER light

4AT(H4DOTC)-98
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
10 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM, throttle
position sensor and ECM.
2) Turn the ignition switch to ON (engine
OFF).
3) Close the throttle completely.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B55) No. 19 (+) — Chassis ground (
−):Is the voltage more than 0.2 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 in throttle posi-
tion sensor circuit.Go to step 20.
11 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM, throttle
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) Close the throttle completely.
6) Read the data of throttle position sensor
using Subaru Select Monitor.
 Throttle position sensor input signal is indi-
cated.Is the voltage more than 0.2 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 in throttle posi-
tion sensor circuit.Go to step 20.
12 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Disconnect the connector from accelerator
pedal position sensor.
2) Measure the resistance between accelera-
tor pedal position sensor connector recepta-
cle’s terminals.
Connector & terminal
No. 1 — No. 2:Is the resistance 0.75 — 3.15
kΩ?Go to step 13.Replace the accel-
erator pedal posi-
tion sensor.
13 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance between accelerator
pedal position sensor connector receptacle’s
terminals.
Connector & terminal
No. 3 — No. 2:Is the resistance 0.15 — 0.63
kΩ?Go to step 14.Replace the accel-
erator pedal posi-
tion sensor.
14 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ACCELERATOR PEDAL POSI-
TION SENSOR.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness
between TCM and accelerator pedal position
sensor connector.
Connector & terminal
(B55) No. 19 — (E13) No. 3:Is the resistance less than 1
Ω?Go to step 15.Repair the open cir-
cuit in harness
between TCM and
accelerator pedal
position sensor
connector, and
poor contact in cou-
pling connector.
15 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ACCELERATOR PEDAL POSI-
TION SENSOR.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 19 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 16.Repair the short cir-
cuit in harness
between TCM and
accelerator pedal
position sensor
connector. Step Check Yes No

4AT(H4DOTC)-99
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
16 CHECK HARNESS CONNECTOR BETWEEN
ECM AND ACCELERATOR PEDAL POSI-
TION SENSOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between accelerator pedal position sensor
connector and chassis ground.
Connector & terminal
(E13) No. 2 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 17.Repair the short
circuit in harness
between ECM and
accelerator pedal
position sensor.
17 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 19.Go to step 18.
18 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) Close the throttle completely.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B55) No. 19 (+) — Chassis ground (
−):Is the voltage more than 0.4 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 of
the connector or
harness may be the
cause. Repair the
harness or connec-
tor in accelerator
pedal position sen-
sor circuit.Go to step 20.
19 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) Close the throttle completely.
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 0.4 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 of
the connector or
harness may be the
cause. Repair the
harness or connec-
tor in accelerator
pedal position sen-
sor circuit.Go to step 20.
20 CHECK POOR CONTACT.Is there poor contact in sensor
circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-103
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK GROUND CIRCUIT OF ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and engine ground.
Connector & terminal
(B134) No. 7 — Engine ground:
(B134) No. 6 — Engine ground:
(B135) No. 1 — Engine ground:
(B135) No. 4 — Engine ground:
(B135) No. 12 — Engine ground:
(B136) No. 19 — Engine ground:
(B137) No. 1 — Engine ground:
(B137) No. 2 — Engine ground:
(B137) No. 7 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair the open cir-
cuit in harness
between ECM con-
nector and engine
ground terminal.
3 CONFIRM MODEL.Is the vehicle 2.0 L model? Go to step 4.Go to step 11.
4 CHECK THROTTLE POSITION SENSOR.
1) Disconnect the connector from throttle
position sensor.
2) Measure the resistance between throttle
position sensor connector receptacle’s termi-
nals.
Connector & terminal
No. 1 — No. 2:Is the resistance 2.5 — 6 kΩ? Go to step 5.Replace the throt-
tle position sensor.
5 CHECK THROTTLE POSITION SENSOR.
Measure the resistance between throttle posi-
tion sensor connector receptacle’s terminals.
Connector & terminal
No. 2 — No. 3:Is the resistance 0.5 — 4.5
kΩ?Go to step 6.Replace the throt-
tle position sensor.
6 CHECK HARNESS CONNECTOR BETWEEN
TCM AND THROTTLE POSITION SENSOR.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness
between TCM connector and chassis ground.
Connector & terminal
(B55) No. 19 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 7.Repair the short
circuit in harness
between TCM and
throttle position
sensor connector.
7 CHECK HARNESS CONNECTOR BETWEEN
ECM AND THROTTLE POSITION SENSOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM connector and throttle position
sensor connector.
Connector & terminal
(E13) No. 2 — (B135) No. 19:Is the resistance less than 1
Ω?Go to step 8.Repair the short
circuit in harness
between ECM and
throttle position
sensor.
8 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 10.Go to step 9.
9 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM, throttle
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 throttle posi-
tion sensor circuit. Step Check Yes No

4AT(H4DOTC)-104
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
10 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM, throttle
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 throttle position sensor
using Subaru Select Monitor.
 Throttle position sensor input signal is indi-
cated.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 throttle posi-
tion sensor circuit.
11 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Disconnect the connector from accelerator
pedal position sensor.
2) Measure the resistance between accelera-
tor pedal position sensor connector recepta-
cle’s terminals.
Connector & terminal
No. 1 — No. 2:Is the resistance 0.75 — 3.15
kΩ?Go to step 12.Replace the accel-
erator pedal posi-
tion sensor.
12 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance between accelerator
pedal position sensor connector receptacle’s
terminals.
Connector & terminal
No. 2 — No. 3:Is the resistance 0.15 — 0.63
kΩ?Go to step 13.Replace the accel-
erator pedal posi-
tion sensor.
13 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ACCELERATOR PEDAL POSI-
TION SENSOR.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness
between TCM connector and chassis ground.
Connector & terminal
(B55) No. 19 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 14.Repair the short
circuit in harness
between TCM and
accelerator pedal
position sensor
connector.
14 CHECK HARNESS CONNECTOR BETWEEN
ECM AND ACCELERATOR PEDAL POSI-
TION SENSOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM connector and accelerator pedal
position sensor connector.
Connector & terminal
(E13) No. 2 — (B135) No. 19:Is the resistance less than 1
Ω?Go to step 15.Repair the short
circuit in harness
between ECM and
accelerator pedal
position sensor.
15 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 17.Go to step 16. Step Check Yes No

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.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

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.
Transmission Con-
trol Module
(TCM).>

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.
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.
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.
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.

4AT(H4DOTC)-117
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
 RHD model
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.
AT-01857
SBF-4 SBF-1
No.13
i10 B:
B54
TCM A:B56
B133 C: C:
i11
C2
B9
C25
A8
E
E
B54
B56
123456
78910 1112
13
14
15 16 17
1819
2021
2223
24
2526
2728
2930
i10
12345678910
i11
5
4 POWER
POWEROFF HOLD
i2B133
12
3456
i3
B3816i2
B3711
i3
219
32
1234 5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
12 345678910111213141516171819202129303122232425262728
POWER AND HOLD
SWITCH BATTERY IGNITION
SWITCH
COMBINATION
METER
123
89
10411 12
13 14 15 1656
7
17
123 8
910411 12 13 14 15 165671718
A:
C:
B:
C: