4AT(H4SO)-16
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Transmission Control Module (TCM) I/O Signal
(1) Transmission control module
(TCM)(17) “P” range indicator light (35) Torque control signal 2
(18) “P” range switch (36) Torque control signal 1
(2) Cruise control module (19) “R” range indicator light (37) Intake manifold pressure signal
(3) ABS control module (20) “R” range switch (38) AT diagnostics signal
(4) Ignition switch (21) “N” range indicator light (39) Engine control module (ECM)
(5) Brake switch (22) “N” range switch (40) ATF temperature sensor
(6) Brake light (23) “D” range indicator light (41) Torque converter turbine speed
sensor
(7) Battery (24) “D” range switch
(8) Combination meter (Speedome-
ter circuit)(25) “3” range indicator light (42) Rear vehicle speed sensor
(26) “3” range switch (43) Front vehicle speed sensor
(9) AT OIL TEMP warning light (27) “2” range indicator light (44) Shift solenoid 1
(10) FWD indicator light (28) “2” range switch (45) Shift solenoid 2
(11) POWER indicator light (29) “1” range indicator light (46) 2-4 brake timing solenoid
(12) FWD switch (30) “1” range switch (47) Line pressure duty solenoid
(13) POWER switch (31) Data link connector (48) 2-4 brake duty solenoid
(14) Kick-down switch (32) Throttle position sensor (49) Lock-up duty solenoid
(15) Hold indicator light (33) Engine speed signal (50) Low clutch timing solenoid
(16) HOLD switch (34) Torque control cut signal (51) Transfer duty solenoid
4AT(H4SO)-18
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Subaru Select Monitor
2. READ CURRENT DATA
1) On the «Main Menu» display screen, select the {Each System Check} and press the [YES] key.
2) On the «System Selection Menu» display screen, select the {Transmission Control System} and press the
[YES] key.
3) Press the [YES] key after the information of transmission type is displayed.
4) On the «Transmission Diagnosis» display screen, select the {Current Data Display & Save} and press the
[YES] key.
5) On the «Data Display Menu» display screen, select the {Data Display} and press the [YES] key.
6) Using the scroll key, move the display screen up or down until desired data is shown.
A list of the support data is shown in the following table.
NOTE:
For detailed operation procedure, refer to the SUBARU SELECT MONITOR OPERATION MANUAL.
Contents Display Unit of measure
Battery voltage Battery Voltage V
Rear vehicle speed sensor signal Rear Wheel Speed km/h or MPH
Front vehicle speed sensor signal Front Wheel Speed km/h or MPH
Engine speed signal Engine Speed rpm
Automatic transmission fluid temperature signal ATF Temp.°C or °F
Throttle position signal Throttle Sensor Voltage V
Gear position Gear Position —
Line pressure control duty ratio Line Pressure Duty Ratio %
Lock up clutch control duty ratio Lock Up Duty Ratio %
Transfer clutch control duty ratio (AWD model) Transfer Duty Ratio %
Power supply for throttle position sensor Throttle Sensor Power V
Torque converter turbine speed signal Turbine Revolution Speed rpm
2-4 brake timing pressure control duty ratio Brake Clutch Duty Ratio %
Intake manifold pressure sensor voltage Mani. Pressure Voltage V
FWD switch signal FWD Switch ON or OFF
Stop light switch signal Stop Light Switch ON or OFF
Anti lock brake system signal ABS Signal ON or OFF
Cruise control system signal Cruise Control Signal ON or OFF
Parking range signal P Range Signal ON or OFF
Neutral range signal N Range Signal ON or OFF
Reverse range signal R Range Signal ON or OFF
Drive range signal D Range Signal ON or OFF
3rd range signal 3rd Range Signal ON or OFF
2nd range signal 2nd Range Signal ON or OFF
1st range signal 1st Range Signal ON or OFF
Shift control solenoid A Shift Solenoid #1 ON or OFF
Shift control solenoid B Shift Solenoid #2 ON or OFF
Torque control output signal #1 Torque Control Signal 1 ON or OFF
Torque control output signal #2 Torque Control Signal 2 ON or OFF
Torque control cut signal Torque Control Cut Sig. ON or OFF
2-4 brake timing control solenoid valve 2-4 Brake Timing Sol. ON or OFF
Low clutch timing control solenoid valve Low Clutch Timing Sol. ON or OFF
Automatic transmission diagnosis indicator lamp Diagnosis Lamp ON or OFF
Power mode switch signal Power Mode Switch ON or OFF
Hold mode switch signal Hold Mode Switch ON or OFF
Kick down switch signal Kick Down Switch ON or OFF
Automatic transmission fluid temperature lamp ATF Temperature Lamp ON or OFF
4AT(H4SO)-24
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Power Indicator Light Display
10.Power Indicator Light Display
A: OPERATION
When any on-board diagnostics item is malfunctioning, the display on POWER indicator light blinks from the
time malfunction is detected after starting the engine until ignition switch is turned to OFF. The malfunctioning
part or unit can be determined by a DTC during on-board diagnostics operation. Problems which occurred
previously can also be identified through the memory function. If the Power indicator does not show a prob-
lem (although a problem is occurring), the problem can be determined by checking the performance charac-
teristics of each sensor using select monitor. The indicator signal is as shown in the figure.
Perform the inspection when the POWER indicator light does not operate correctly.
(A) Ignition switch (engine OFF) (C) Faulty (engine ON) (D) Normal (POWER switch ON)
(B) Normal (engine ON)
(1) ON (4) 0.25 sec. (6) POWER switch ON
(2) OFF (5) Blink (7) POWER switch OFF
(3) 2 sec.
AT-01109
(4)
(3)
(1)
(2)
(1)
(2)
(1)
(2)
(1)
(2)(3)
(3)(5)
(6) (A)
(B)
(C)
(D)
(7)
4AT(H4SO)-35
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
12.List of Diagnostic Trouble Code (DTC)
A: LIST
DTC Item Content of diagnosis Index
11 Engine speed signalDetects open or shorted input
signal circuit.
Trouble Code (DTC).>
27 ATF temperature sensorDetects open or shorted input
signal circuit.
nostic Trouble Code (DTC).>
31 Throttle position sensorDetects open or shorted input
signal circuit.
Diagnostic Trouble Code (DTC).>
33Front vehicle speed
sensorDetects open or shorted input
signal circuit.
Diagnostic Trouble Code (DTC).>
36Torque converter tur-
bine speed sensorDetects open or shorted input
signal circuit.
Procedure with Diagnostic Trouble Code (DTC).>
38 Torque control signalDetects open or shorted input
signal circuit.
nostic Trouble Code (DTC).>
45Intake manifold pres-
sure signalDetects open or shorted input
signal circuit.
dure with Diagnostic Trouble Code (DTC).>
71 Shift solenoid 1Detects open or shorted out-
put signal circuit.
Trouble Code (DTC).>
72 Shift solenoid 2Detects open or shorted out-
put signal circuit.
Trouble Code (DTC).>
73Low clutch timing sole-
noidDetects open or shorted out-
put signal circuit.
Diagnostic Trouble Code (DTC).>
742-4 brake timing sole-
noidDetects open or shorted out-
put signal circuit.
nostic Trouble Code (DTC).>
75Line pressure duty sole-
noidDetects open or shorted out-
put signal circuit.
with Diagnostic Trouble Code (DTC).>
76 2-4 brake duty solenoidDetects open or shorted out-
put signal circuit.
Diagnostic Trouble Code (DTC).>
77 Lock-up duty solenoidDetects open or shorted out-
put signal circuit.
Trouble Code (DTC).>
79 Transfer duty solenoidDetects open or shorted out-
put signal circuit.
Diagnostic Trouble Code (DTC).>
93Rear vehicle speed
sensorDetects open or shorted input
signal circuit.
Diagnostic Trouble Code (DTC).>
4AT(H4SO)-38
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
B: DTC 27 ATF TEMPERATURE SENSOR
DTC DETECTING CONDITION:
The input signal circuit of TCM to ATF temperature sensor is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
WIRING DIAGRAM:
AT-00776
11
20 11
12 ATF TEMPERATURE
SENSOR
B54
B11
T4 TCM
B11TRANSMISSION
125678
131415169101112
34
17181920
B54
1234
10
11 12
19 20 21135614 1578916 17 18
22 23 24
4AT(H4SO)-39
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion and TCM.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B54) No. 20 — (B11) No. 12:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ATF TEMPERATURE SENSOR.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B54) No. 11 — (B11) No. 11:Is the resistance less than 1
Ω?Go to step 3.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ATF TEMPERATURE SENSOR.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 20 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ATF TEMPERATURE SENSOR.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 11 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
5 CHECK ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the connectors to transmission
and TCM.
3) Turn the ignition switch to ON and start
engine.
4) Warm-up the transmission until ATF tem-
perature reaches to 80°C (176°F).
NOTE:
If ambient temperature is below 0°C (32°F),
drive the vehicle until ATF reaches its operating
temperature.
5) Disconnect the connector from transmis-
sion.
6) Measure the resistance between transmis-
sion connector terminals.
Connector & terminal
(T4) No. 11 — No. 12:Is the resistance 275 — 375
Ω?Go to step 6.Replace the ATF
temperature sen-
sor.
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
6 CHECK ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Measure the resistance between transmis-
sion connector terminals.
Connector & terminal
(T4) No. 11 — No. 12:Does the resistance value
increase while ATF tempera-
ture decreases? Go to step 7.Replace the ATF
temperature sen-
sor.
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
7 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 9.Go to step 8.
4AT(H4SO)-40
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connector to transmission.
2) Warm-up the transmission until ATF tem-
perature is about 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) Measure the voltage between TCM con-
nector terminal.
Connector & terminal
(B54) No. 11 (+) — No. 20 (
−):Is the voltage 0.4 — 0.9 V? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. Tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
contact in ATF
temperature sen-
sor and transmis-
sion connector.Go to step 10.
9 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connector to transmission.
2) Turn the ignition switch to ON (engine OFF).Does the ATF temperature
gradually decrease?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. Tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
contact in ATF
temperature sen-
sor and transmis-
sion connector.Go to step 10.
10 CHECK POOR CONTACT.Is there poor contact in ATF
temperature sensor circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).> Step Check Yes No
4AT(H4SO)-41
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
C: DTC 31 THROTTLE POSITION SENSOR
DTC DETECTING CONDITION:
The input signal circuit of throttle position sensor is open or shorted.
TROUBLE SYMPTOM:
Shift point too high or too low
Excessive shift shock
Tight corner braking phenomenon
WIRING DIAGRAM:
AT-01825
B134B136B135
12
910 11 21
242512
893
10
212212
8
93
105
1711
2212 13
2314
2415
25
204
16
26 2167
1819
272834
12 13
2627161718
303114 15
28
2978
22
23
343556
19 20
32
33
B54B122
1234
56789
10 1112
13 14 15 16 17 18
192021
2223 24
18131415
25
2611 12
23246
7
192045
16 17
B22
1
234
56
78
9
1314
15
20
19 1716 10 11
12
18
B21
E13
B122
B21
B134B54 TCM
A:B135 B:
B136ECM
C:
E2
B22
E3
E13
13 1415
16
12 34
12 3456 78
9
10
11
12
B13
B3
15
13816
14B19
4
3
22
3
C26D14B21C16C5A35A7
EE
2
1
12
11
9
SHIELD AND
THROTTLE
POSITION SENSORSENSOR GROUND
JOINT CONNECTOR
B122: RHD
: LHD
12
893
10
1813141511 1267
19204
5
16 17
B137
B137 D:
12345678
D:
B:
A: C: