
5AT(diag)-30
List of Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
P0957Backup Light Relay Cir-
cuit Low
Back-up relay output circuit is
open, shorted or relay OFF mal-
function
dure with Diagnostic Trouble Code (DTC).>
P0958Backup Light Relay Out-
put Circuit High
Back-up relay output circuit is
open, shorted or relay ON mal-
function
cedure with Diagnostic Trouble Code (DTC).>
P1601TCM Data Communica-
tion Failure
Communication Failure between
TCM and Memory Box
dure with Diagnostic Trouble Code (DTC).>
P1706
AT Ve h i c l e S p e e d S e n -
sor Circuit Malfunction
(Rear Wheel)
Rear wheel speed sensor is faulty
or input circuit, ground, power
supply is open or shorted.
TION (REAR WHEEL), Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P1707AT A W D S o l e n o i d V a l v e
Circuit Malfunction
AWD solenoid circuit malfunction
or AWD solenoid body malfunc-
tion
Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1710
To r q u e C o n v e r t e r Tu r -
bine 2 Speed Signal Cir-
cuit 2 Malfunction
To r q u e c o n v e r t e r s e n s o r 2 m a l -
function, input circuit, ground,
power open, short circuit
CIRCUIT 2 MALFUNCTION, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P1716AT F Te m p . S e n s o r 2 C i r -
cuit Low
AT F t e m p e r a t u r e s e n s o r 2 m a l -
function, or open input signal cir-
cuit
dure with Diagnostic Trouble Code (DTC).>
P1717AT F Te m p . S e n s o r 2 C i r -
cuit High
AT F t e m p e r a t u r e s e n s o r 2 m a l -
function, short input signal circuit
dure with Diagnostic Trouble Code (DTC).>
P1718AT C A N C o m m u n i c a t i o n
Circuit
CAN communication line bus off
is open, EUM short circuit, ABS/
VDCCM, integrated CU malfunc-
tion
dure with Diagnostic Trouble Code (DTC).>
P1798 Gear 1 Engine Brake
Malfunction of clutch oil pressure
related to 1st engine brake, sole-
noid current malfunction
Diagnostic Trouble Code (DTC).>
P1799 Interlock
Malfunction of clutch oil pressure
which emit interlock, solenoid
current malfunction
Tr o u b l e C o d e ( D T C ) . >
P1817SPORT Mode Switch
Circuit (Manual Switch)
Manual mode switch is open or
shorted, or switch malfunction
Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1840
Tr a n s m i s s i o n F l u i d P r e s -
sure Sensor/Switch A
Circuit
Fr/B oil pressure switch is open or
shorted, or switch malfunction
CIRCUIT, Diagnostic Procedure with Diagnostic
Tr o u b l e C o d e ( D T C ) . >
P1842
Tr a n s m i s s i o n F l u i d P r e s -
sure Sensor/Switch C
Circuit
I/C oil pressure switch is open or
shorted, or switch malfunction.
CIRCUIT, Diagnostic Procedure with Diagnostic
Tr o u b l e C o d e ( D T C ) . >
P1843
Tr a n s m i s s i o n F l u i d P r e s -
sure Sensor/Switch D
Circuit
D/C oil pressure switch is open or
shorted, or switch malfunction.
CIRCUIT, Diagnostic Procedure with Diagnostic
Tr o u b l e C o d e ( D T C ) . >
P1844
Tr a n s m i s s i o n F l u i d P r e s -
sure Sensor/Switch E
Circuit
H&LR/C oil pressure switch is
open or shorted, or switch mal-
function.
CIRCUIT, Diagnostic Procedure with Diagnostic
Tr o u b l e C o d e ( D T C ) . >
DTC Item Content of diagnosis Reference target

5AT(diag)-44
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
E: DTC P0719 TORQUE CONVERTER/BRAKE SWITCH “B” CIRCUIT LOW
DTC DETECTING CONDITION:
Brake switch malfunction, open input signal circuit
TROUBLE SYMPTOM:
Brake down control is not operated at SPORT mode.
WIRING DIAGRAM:
AT-03287
STOP LIGHTSWITCH
B65
BODY INTEGRATEDUNIT
B280A:
B281B:
B23
A20A30
B159
213489765
2
1
43
TCMB54
BATTERY
MAIN SBF SBF-2
NO.8
E
87654321
212220191615141312111091718282726252423
B281B:
87654321
2223212019161514131211109173018292827262524
B280A:
B54
12789563410 11 1219 20 2113 14 15 16 17 18222324
B65
1234

5AT(diag)-45
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step Check Yes No
1CHECK DTC.Is any of following DTC dis-
played? / AT CAN Communica-
tion Circuit / Output Speed
Sensor Circuit / AT Vehicle
Speed Sensor Circuit Malfunc-
tion (Rear Wheel)
Pe r for m t h e d ia g -
nosis according to
DTC.
Go to step 2.
2CHECK THE BODY INTEGRATED UNIT.
1) Turn the ignition switch to OFF.
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) Depress the brake pedal.
6) Read the data of brake pedal switch using
Subaru Select Monitor.
Is ON displayed? Go to step 3.Go to step 4.
3CHECK TCM.
Read the data of brake pedal switch using
Subaru Select Monitor.
Is ON displayed? A temporary poor
contact of connec-
tor or harness may
be the cause.
Check the poor
contact.
Replace the TCM.
trol Module
(TCM).>
4CHECK BODY INTEGRATED UNIT INPUT
SIGNAL.
1) Disconnect the connector from body inte-
grated unit.
2) Depress the brake pedal.
3) Measure the voltage between body inte-
grated unit connector and chassis ground.
Connector & terminal
(B281) No. 23 (+) — Chassis ground (–):
Is the voltage more than 10 V? Go to step 7.Go to step 5.
5CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND STOP LIGHT
SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light
switch.
3) Measure the resistance of harness
between body integrated unit and stop light
switch.
Connector & terminal
(B281) No. 23 — (B64) No. 2:
Is the resistance less than 1
Ω?
Go to step 6.Repair the open
circuit of harness
between body inte-
grated unit and
stop light switch.
6CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND STOP LIGHT
SWITCH.
Measure the resistance of harness between
body integrated unit connector and stop light
switch.
Connector & terminal
(B281) No. 23 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 7.Repair the short
circuit of harness
between body inte-
grated unit and
stop light switch.
7CHECK POOR CONTACT.Is there poor contact in input
signal of brake switch?
Repair the poor
contact.
Check the body
integrated unit.

5AT(diag)-50
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
G: DTC P0724 TORQUE CONVERTER/BRAKE SWITCH “B” CIRCUIT HIGH
DTC DETECTING CONDITION:
Brake switch malfunction, open input signal circuit
TROUBLE SYMPTOM:
Gear is not shifted down when climbing a hill.
WIRING DIAGRAM:
AT-03287
STOP LIGHTSWITCH
B65
BODY INTEGRATEDUNIT
B280A:
B281B:
B23
A20A30
B159
213489765
2
1
43
TCMB54
BATTERY
MAIN SBF SBF-2
NO.8
E
87654321
212220191615141312111091718282726252423
B281B:
87654321
2223212019161514131211109173018292827262524
B280A:
B54
12789563410 11 1219 20 2113 14 15 16 17 18222324
B65
1234

5AT(diag)-51
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step Check Yes No
1CHECK DTC.Is any of following DTC
detected? / AT CAN Communi-
cation Circuit / Output Speed
Sensor Circuit / AT Vehicle
Speed Sensor Circuit Malfunc-
tion (Rear Wheel)
Pe r for m t h e d ia g -
nosis according to
DTC.
Go to step 2.
2CHECK THE BODY INTEGRATED UNIT.
1) Turn the ignition switch to OFF.
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) Read the data of brake pedal switch using
Subaru Select Monitor.
Is OFF displayed? Go to step 3.Go to step 4.
3CHECK TCM.
Read the data of brake pedal switch using
Subaru Select Monitor.
Is OFF displayed? A temporary poor
contact of connec-
tor or harness may
be the cause.
Check the poor
contact.
Replace the TCM.
trol Module
(TCM).>
4CHECK BODY INTEGRATED UNIT INPUT
SIGNAL.
1) Disconnect the connector from body inte-
grated unit.
2) Measure the voltage between body inte-
grated unit connector and chassis ground.
Connector & terminal
(B281) No. 23 (+) — Chassis ground (–):
Is the voltage more than 10 V? Go to step 5.Go to step 7.
5CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light
switch.
3) Measure the resistance of harness
between stop light switch connectors.
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 stop
light switch.
6CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND STOP LIGHT
SWITCH.
1) Turn the ignition switch to ON.
2) Measure the voltage of harness between
body integrated unit connector and chassis
ground.
Connector & terminal
(B281) No. 23 (+) — Chassis ground (–):
Is the voltage less than 1 V? Go to step 7.Repair the short
circuit of harness
between TCM and
stop light switch.
7CHECK POOR CONTACT.Is there poor contact in input
signal of brake switch?
Repair the poor
contact.
Check the body
integrated unit.

5AT(diag)-61
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
R: DTC P0751 SHIFT SOLENOID “A” PERFORMANCE OR STUCK OFF
DTC DETECTING CONDITION:
Output signal of front brake solenoid does not match with oil pressure.
TROUBLE SYMPTOM:
Locked to 4th or 5th gear.
WIRING DIAGRAM:
AT-02937
A:
A24B17
173
911
B11
B54
B11
125678
131415169101112
34
17181920
TRANSMISSION
12789563410 11 1219 20 2113 14 15 16 17 18222324
T4
T6
12586910 113412
T6
7
E
514
T5
12341011 121920 21135614 1578916 17 1822 23 24
B55B:
123 68910 11 12 13 14451516
T5
7
B54
B55
A:
B:
TCM

5AT(diag)-64
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
S: DTC P0753 SHIFT SOLENOID “A” ELECTRICAL
DTC DETECTING CONDITION:
Output signal circuit of front brake solenoid is open or shorted.
TROUBLE SYMPTOM:
Locked to 4th or 5th gear.
WIRING DIAGRAM:
AT-02987
A:
A24
B11
B54
B11
125678
131415169101112
34
17181920
TRANSMISSION
12789563410 11 1219 20 2113 14 15 16 17 18222324
T4
T6
12586910 113412
T6
7
17
E
514
9
12341011 121920 21135614 1578916 17 1822 23 24
B55B:
B54
B55
A:
B:
TCM

5AT(diag)-65
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step Check Yes No
1CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
transmission.
3) Measure the resistance of harness
between TCM connector and transmission
connector.
Connector & terminal
(B54) No. 24 — (B11) No. 17:
(B54) No. 5 — Chassis ground:
(B54) No. 14 — Chassis ground:
Is the resistance less than 1
Ω?
Go to step 2.Repair the open
circuit of harness
between TCM con-
nector and trans-
mission connector.
2CHECK HARNESS CONNECTOR BETWEEN
TCM AND CHASSIS GROUND.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 24 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 3.Repair the short
circuit of harness
between TCM con-
nector and trans-
mission connector.
3CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND CONTROL VALVE
BODY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Remove the transmission connector from
bracket.
4) Lift-up the vehicle and place it on rigid
racks.
NOTE:
Raise all wheels off floor.
5) Drain the ATF.
CAUTION:Do not drain ATF until it cools down.
6) Remove the oil pan, and disconnect the
control valve body connector.
7) Measure the resistance between transmis-
sion connector and control valve body connec-
tor.
Connector & terminal
(T4) No. 17 — (T6) No. 9:
Is the resistance less than 1
Ω?
Go to step 4.Repair the open
circuit of harness
between transmis-
sion connector
and control valve
body connector.
4CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND CONTROL VALVE
BODY.
Measure the resistance between transmission
ground and control valve body connector.
Connector & terminal
(T6) No. 9 — Transmission ground:
Is the resistance more than 1
MΩ?
Go to step 5.Repair the short
circuit of harness
between control
valve body and
transmission con-
nector.
5CHECK FRONT BRAKE SOLENOID.
Measure the resistance between transmission
ground and control valve body connector.
Connector & terminal
(T6) No. 9 — Transmission ground:
Is the resistance between 3 —
9 Ω?
Go to step 6.Replace the con-
trol valve body.
Body.>