2004 SUBARU FORESTER check engine

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)-102
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
 RHD model
Step Check Yes No
1 CHECK ENGINE GROUND TERMINALS.Have the engine ground termi-
nals been tightened securely?Go to step 2.Tighten the engine
ground terminals.
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)-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)-118
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
2 CHECK POWER SWITCH OPERATION.When the POWER switch is
turned to ON, does LED light
up?Go to step CHECK
HOLD SWITCH.
4AT(H4DOTC)-
120, CHECK
HOLD 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.Replace the
POWER indicator
light bulb. IDI-10, Combina-
tion Meter Assem-
bly.>
4 CHECK POWER SWITCH GROUND CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from POWER
switch.
3) Measure the resistance of harness connector
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.Replace 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 than1
MΩ?Go to step 7.Replace 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
(B54) No. 8 — (B133) No. 5: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 connector and chassis ground.
Connector & terminal
(B54) No. 8 — 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.
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
(B54) No. 8 (+) — Chassis ground (–):Is the voltage more than 10 V? Go to step 10.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-125
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
3 CHECK KICK-DOWN SWITCH GROUND
LINE.
1) Disconnect the connector from kick-down
switch.
2) Measure the resistance of harness connector
between kick-down switch and chassis ground.
Connector & terminal
(B129) No. 1 — Chassis ground:Is the resistance less than 1
Ω?Go to step 4.Repair the open cir-
cuit in harness
between kick-down
switch and TCM.
4 CHECK KICK-DOWN SWITCH.
Measure the resistance for kick-down switch
when depressing the accelerator pedal.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 1
Ω?Go to step 5.Replace the kick-
down switch. to SP(H4SO)-4,
Accelerator
Pedal.>
5 CHECK KICK-DOWN SWITCH.
Measure the resistance for kick-down switch
when pressing the accelerator pedal.
Te r m i n a l s
No. 1 — No. 2:Is the resistance more than 1
MΩ?Go to step 6.Replace the kick-
down switch.
6 CHECK HARNESS CONNECTOR BETWEEN
TCM AND KICK-DOWN SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from kick-down
switch.
3) Measure the resistance of harness connec-
tor between TCM and kick-down switch.
Connector & terminal
(B54) No. 11 — (B129) No. 2:Is the resistance less than 1
Ω?Go to step 7.Repair the open
circuit in harness
between TCM and
kick-down switch.
7 CHECK HARNESS CONNECTOR BETWEEN
TCM AND KICK-DOWN SWITCH.
Measure the resistance of harness connector
between TCM connector and chassis ground.
Connector & terminal
(B54) No. 11 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 8.Repair the short
circuit in harness
between TCM and
chassis ground.
8 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to kick-down switch.
3) Turn the ignition switch to ON (engine OFF).
4) Measure the signal voltage for TCM when
not depressing the accelerator pedal.
Connector & terminal
(B55) No. 11 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 9.Go to step 10.
9 CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM when press-
ing the accelerator pedal.
Connector & terminal
(B55) No. 11 (+) — Chassis ground (
−):Is the voltage more than 6.5 V? A temporary poor
contact of the con-
nector and har-
ness may be the
cause. Repair the
harness and con-
nector in TCM.Go to step 10.
10 CHECK POOR CONTACT.Is there poor contact? Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No