Subaru 2009 IMPREZA Service Manual page 2024

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmission
and TCM.
3) Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B55) No. 12 — (B11) No. 15:
(B55) No. 23 — (B11) No. 11:
2 CHECK ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the connectors to transmission and
TCM.
3) Start the engine.
4) Warm up the transmission until the ATF
temperature exceeds 80°C (176°F).
5) Disconnect the connector from transmis-
sion.
6) Measure the resistance between transmis-
sion connector terminals.
Connector & terminal
(T4) No. 11 — No. 15:
3 CHECK ATF TEMPERATURE SENSOR.
Measure the resistance between transmission
connector terminals.
Connector & terminal
(T4) No. 11 — No. 15:
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connector to transmission.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON.
4) Read the data of "ATF temperature sensor"
using Subaru Select Monitor.
5 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND ATF TEMPERATURE
SENSOR.
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.
5) Drain the automatic transmission fluid.
CAUTION:
Do not drain ATF until it cools down.
6) Remove the oil pan.
7) Disconnect the control valve connector.
8) Measure the resistance of harness between
ATF temperature sensor and transmission con-
nector.
Connector & terminal
(T4) No. 11 — (AT2) No. 4:
(T4) No. 15 — (AT2) No. 9:
6 CHECK POOR CONTACT.
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Check
Is the resistance less than 1 ? Go to step 2.
Is the resistance 300 — 800 ? Go to step 3.
Does the resistance value
increase while the ATF temper-
ature decreases?
Does the ATF temperature
gradually decrease?
Is the resistance less than 1 ? Replace the con-
Is there poor contact of ATF
temperature sensor circuit?
4AT(diag)-39
Yes No
Repair the open
circuit of harness
between TCM and
transmission con-
nector.
Go to step 6.
Go to step 4. Go to step 6.
Check the connec- Go to step 5.
tors or harnesses
between ATF tem-
perature sensor
and transmission,
and repair the
defective part.
Repair the open
trol valve body. circuit of harness
<Ref. to 4AT-58, between ATF tem-
Control Valve perature sensor
Body.> and transmission
connector.
Repair the poor Replace the TCM.
contact. <Ref. to 4AT-63,
Transmission Con-
trol Module
(TCM).>