2004 SUBARU FORESTER check engine

4AT(H4DOTC)-80
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK OUTPUT SIGNAL FROM TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
3) Start the engine and warm-up the engine
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) Shift the select lever to “D” range and
slowly increase vehicle speed and measure at
3rd or 4th gear.
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
(B56) No. 8 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 9.
6 CHECK OUTPUT SIGNAL FROM TCM.
1) Return the engine to idling speed and shift
select lever to “N” range.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B56) No. 8 (+) — Chassis ground (
−):Is the voltage more than 10.5
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 TCM and
transmission.Go to step 9. Step Check Yes No

4AT(H4DOTC)-81
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
3) Connect the Subaru Select Monitor to data
link connector.
4) Start the engine and turn Subaru Select
Monitor switch to ON.
5) Start the engine and warm-up the engine
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.
6) Read the data of high clutch duty solenoid
using Subaru Select Monitor.
 High clutch duty solenoid is indicated in “%”.
7) Shift the select lever to “D” range and
slowly increase vehicle speed and measure at
3rd or 4th gear.
NOTE:
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.>Is the value 0%? Go to step 8.Go to step 9.
8 CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
Return the engine to idling speed and shift
select lever to “N” range.
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.>Is the value 100%? 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 TCM and
transmission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in high
clutch duty circuit?Repair poor con-
tact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-84
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK OUTPUT SIGNAL FROM TCM.
1) Connect all connectors.
2) Start the engine and warm-up the engine
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) Shift the select lever to “N” range.
5) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B56) No. 7 (+) — Chassis ground (
−):Is the voltage more than 10.5
V?Go to step 6.Go to step 9.
6 CHECK OUTPUT SIGNAL FROM TCM.
1) Shift the select lever to “1” range.
2) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B56) No. 7 (+) — Chassis ground (
−):Is the voltage less than 5 — 9
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 TCM and
transmission.Go to step 9.
7 CHECK OUTPUT SIGNAL FROM TCM US-
ING 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).
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) Read the data of low & reverse duty sole-
noid using Subaru Select Monitor.
 Low & reverse brake duty solenoid is indi-
cated in “%”.Is the value 100%? Go to step 8.Go to step 9. Step Check Yes No

4AT(H4DOTC)-87
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND N–R LOCK SOLENOID.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B56) No. 18 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
N–R lock solenoid
connector.
3 CHECK HARNESS CONNECTOR BETWEEN
N–R LOCK SOLENOID AND CHASSIS
GROUND.
Measure the resistance of harness between
N–R lock solenoid and chassis ground.
Connector & terminal
(B117) No. 5 — Chassis ground:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit in harness
between chassis
ground terminal
and N–R lock sole-
noid connector.
4 CHECK N–R LOCK SOLENOID.
Measure the resistance between N–R lock
solenoid.
Connector & terminal
(B117) No. 5 — No. 4:Is the resistance 20 — 40 Ω? Go to step 5.Replace the N–R
lock solenoid.
5 CHECK TCM OUTPUT SIGNAL.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Shift the select lever to “D” range.
4) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B56) No. 18 (+) — Chassis ground (
−):Is the voltage more than 10.5
V?Go to step 6.Go to step 7.
6 CHECK OUTPUT SIGNAL FROM TCM.
1) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
2) Start the engine.
3) Shift the select lever “D” range and slowly
increase vehicle speed to 20 km/h (12 MPH).
NOTE:
The speed difference between front and rear
wheels may light ABS warning light, but this indi-
cates no malfunction. When AT control diagnosis
is finished, perform the ABS memory clearance
procedure of on-board diagnostics system.
4) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B56) 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
normal condition at
this time. A tempo-
rary poor contact of
the connector or
harness may be
cause. Repair the
harness or connec-
tor in reverse inhibi-
tor control circuit.Go to step 7.
7 CHECK POOR CONTACT.Is there poor contact in the
reverse inhibitor control circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-90
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
3) Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
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.>
4) Measure the AC voltage between TCM
connector terminals.
Connector & terminal
(B55) No. 24 (+) — No. 23 (
−):Is the voltage more than AC 2
V?Go to step 10.Replace the rear
vehicle speed sen-
sor.
9 CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up the vehicle and place rigid racks.
NOTE:
Raise all wheels off ground.
3) Set the oscilloscope to TCM connector ter-
minals.
Connector & terminal
Positive probe; (B55) No. 24:
Earth lead; (B55) No. 23:
4) Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
NOTE:
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 signal voltage indicated on
oscilloscope.Is the voltage more than AC 2
V?Go to step 10.Replace the rear
vehicle speed sen-
sor.
10 CHECK POOR CONTACT.Is there poor contact in rear
vehicle speed sensor circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-92
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK OUTPUT SIGNAL FROM TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Turn the ignition switch to ON (engine OFF).
3) Shift the select lever to “P” range.
4) Throttle is fully closed.
5) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B56) No. 4 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 9.
6 CHECK OUTPUT SIGNAL FROM TCM.
1) Shift the select lever to “D” range.
2) Measure the voltage between TCM con-
nector and chassis ground with throttle fully
open.
Connector & terminal
(B56) No. 4 (+) — Chassis ground (
−):Is the voltage more than 10.5
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 TCM and
transmission.Go to step 9.
7 CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and trans-
mission.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON (engine OFF)
and turn Subaru Select Monitor switch to ON.
4) Move the select lever to “N” range with
throttle fully close (vehicle speed 0 km/h (0
MPH)).
5) Read data of transfer duty solenoid using
Subaru Select Monitor.
 Transfer duty solenoid is indicated in “%”.Is the value 5%? Go to step 8.Go to step 9.
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Shift the select lever to “D” range with throt-
tle fully open (vehicle speed 0 km/h (0 MPH)).
2) Read the data of transfer duty solenoid
using Subaru Select Monitor.
 Transfer duty solenoid is indicated in “%”.Is the value 90 — 95%? 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 TCM and
transmission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in transfer
duty solenoid circuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-96
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
 RHD model
Step Check Yes No
1 CHECK ENGINE GROUND TERMINALS.Have engine ground terminals
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)-97
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. 6 — Engine ground:
(B134) No. 7 — 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
grounding terminal.
3 CONFIRM MODEL.Is the vehicle 2.0 L model? Go to step 4.Go to step 12.
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. 3 — No. 2: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 and throttle position sensor connector.
Connector & terminal
(B55) No. 19 — (E13) No. 3:Is the resistance less than 1
Ω?Go to step 7.Repair the open cir-
cuit in harness
between TCM and
throttle position
sensor connector,
and poor contact in
coupling connector.
7 CHECK HARNESS CONNECTOR BETWEEN
TCM AND THROTTLE POSITION 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 8.Repair the short
circuit in harness
between TCM and
throttle position
sensor connector.
8 CHECK HARNESS CONNECTOR BETWEEN
ECM AND THROTTLE POSITION SENSOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness between
throttle position sensor and chassis ground.
Connector & terminal
(E13) No. 2 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 9.Repair the short
circuit in harness
between ECM and
throttle position
sensor.
9 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 11.Go to step 10. Step Check Yes No