SUBARU FORESTER 2004 Service Repair Manual

4AT(H4DOTC)-85
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
1) Shift the select lever to “1” range.
2) Read the data of low & reverse duty sole-
noid.Is the value 61.5%? 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 low &
reverse duty solenoid circuit?Repair the poor
contact.Replace the TCM.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).>
10 CHECK LOW & REVERSE BRAKE DUTY
SOLENOID (IN TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the oil pan, and disconnect con-
nector from low & reverse brake duty solenoid.
4) Measure the resistance between low &
reverse brake duty solenoid connector and
transmission ground.
Connector & terminal
(AT12) No. 1 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the control
valve body. <Ref. to
4AT-61, Control
Valve Body.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LOW & REVERSE
BRAKE DUTY SOLENOID.
Measure the resistance of harness between
low & reverse brake duty solenoid and trans-
mission connector.
Connector & terminal
(T4) No. 6 — (AT12) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between low &
reverse brake duty
solenoid and
transmission con-
nector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LOW & REVERSE
BRAKE DUTY SOLENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 6 — Transmission ground:Is the resistance more than 1
MΩ?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 low & reverse
brake duty solenoid
and transmission.Repair the short
circuit in harness
between low &
reverse brake duty
solenoid and
transmission con-
nector. Step Check Yes No

4AT(H4DOTC)-86
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
U: DTC P0801 REVERSE INHIBITOR CONTROL CIRCUIT
DTC DETECTING CONDITION:
N–R lock solenoid malfunction, open or short reverse inhibitor control circuit.
TROUBLE SYMPTOM:
 Gear is shifted from “N” range to “R” range during driving at 20 km/h (12 MPH) or more.
 Gear can not be shifted from “N” range to “R” range.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND N–R LOCK SOLENOID.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
N–R lock solenoid.
3) Measure the resistance harness between
TCM and N–R lock solenoid connector.
Connector & terminal
(B56) No. 18 — (B117) No. 4:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
N–R lock solenoid
connector.
AT-01849
TCM
N-R LOCK SOLENOID
18
B56
E
B117
B56
B117
4
5
12
789 56 3
410 11 1219 20 21
29 30 31 13 14 15 1617
27 2818
22 23 24 25 26
12
3456

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.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-88
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
V: DTC P1706 AT VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION (REAR
WHEEL)
DTC DETECTING CONDITION:
Input signal circuit of TCM is open or shorted.
TROUBLE SYMPTOM:
No lock-up or tight corner “braking” phenomenon.
WIRING DIAGRAM:
AT-01850
2324
B11
AT10
T491713
312
B55 TCM BATTERY
IGNITION
SWITCH
REAR VEHICLE
SPEED SENSOR
ESBF-1
SBF-4 NO.11
123
AT10B11
12 34
5678
9
13 14 15
20 19 1716 10 11 1218
B55
12 7
8956 34
10 11 12
19 20 2113 14 15 16
17 18 22 23 24

4AT(H4DOTC)-89
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK IGNITION POWER SUPPLY CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear vehicle
speed sensor.
3) Turn the ignition switch to ON.
4) Measure the ignition power supply voltage
between rear vehicle speed sensor connector
and transmission ground.
Connector & terminal
(AT10) No. 3 (+) — Transmission ground
(
−):Is the voltage more than 10 V? Go to step 2.Check harness
between rear vehi-
cle speed sensor
and battery for
open circuit, short
or poor contact.
Repair the har-
ness if required.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND REAR VEHICLE SPEED SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between
TCM and rear vehicle speed sensor connector.
Connector & terminal
(B55) No. 23 — (AT10) No. 1:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit or poor con-
tact of connector in
harness between
TCM and rear
vehicle speed sen-
sor connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND REAR VEHICLE SPEED SENSOR.
Measure the resistance of harness between
TCM and rear vehicle speed sensor connector.
Connector & terminal
(B55) No. 24 — (AT10) No. 2:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit or poor con-
tact of connector in
harness between
TCM and rear
vehicle speed sen-
sor connector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 23 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
rear vehicle speed
sensor connector.
5 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 24 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair the short
circuit in harness
between TCM and
rear vehicle speed
sensor connector.
6 CHECK OUTPUT SIGNAL FROM TCM.
1) Connect the connector to TCM.
2) Turn the ignition switch to ON.
3) Measure the voltage between transmission
connector terminals.
Connector & terminal
(B55) No. 24 (+) — No. 24 (
−):Is the voltage approx. 5 V? Go to step 7.Go to step 10.
7 PREPARE OSCILLOSCOPE.Do you have an oscilloscope? Go to step 9.Go to step 8.

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. <Ref. to ABS-23, Clear Memory
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. <Ref. to ABS-23, Clear Memory
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.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-91
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
W: DTC P1707 AT AWD SOLENOID VALVE CIRCUIT MALFUNCTION
DTC DETECTING CONDITION:
Output signal circuit of transfer duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Tight corner “braking” phenomenon occurs or drive system changes to FWD.
WIRING DIAGRAM:
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
transmission.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B56) No. 4 — (B11) No. 8:Is the resistance less than 1 ΩGo to step 2.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance harness connector
between TCM and chassis ground.
Connector & terminal
(B56) No. 4 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
3 CHECK TRANSFER DUTY SOLENOID.
Measure the resistance between transmission
connector and transmission terminals.
Connector & terminal
(T4) No. 8 — No. 20:Is the resistance 2.0 — 4.5 Ω? Go to step 4.Go to step 10.
4 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 7.Go to step 5.
AT-01122
B11
B56
AT12
1
234
56
78
9
1314
15
20
19 1716 10 1112
18
4
B56
B11
AT12
T4 TCM8 512 78 956 34
10 11 12 19 20 21
29 30 31 13 14 15 16 17
27 2818
22 23 24 25 26
13
4562
TRANSMISSIONTRANSFER
DUTY
SOLENOID

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.
<Ref. to 4AT-77,
Transmission Con-
trol Module
(TCM).> Step Check Yes No

4AT(H4DOTC)-93
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
10 CHECK TRANSFER DUTY SOLENOID (IN
TRANSMISSION).
1) Lift-up the vehicle and place rigid racks.
N
OTE:
Raise all wheels off ground.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the extension case and disconnect
connector from transfer duty solenoid.
4) Measure the resistance between transfer
duty solenoid connector and transmission
ground.
Connector & terminal
(AT12) No. 5 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the con-
trol valve body.
<Ref. to 4AT-61,
Control Valve
Body.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSFER DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transfer duty solenoid and transmission con-
nector.
Connector & terminal
(T4) No. 8 — (AT12) No. 5:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between transfer
duty solenoid and
transmission con-
nector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSFER DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 8 — Transmission ground:Is the resistance more than 1
MΩ?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 contact
in transfer duty
solenoid and trans-
mission.Repair the short
circuit in harness
between transfer
duty solenoid and
transmission con-
nector. Step Check Yes No

4AT(H4DOTC)-94
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
X: DTC P1708 THROTTLE POSITION SENSOR CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
 Input signal circuit of throttle position sensor is open or shorted. (2.0 L model)
 Input signal 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.