Subaru 2009 IMPREZA Service Manual page 2039

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
1 CHECK DTC.
2 CHECK 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
(B55) No. 6 — (B11) No. 12:
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of the harness connec-
tor between TCM connector and chassis
ground.
Connector & terminal
(B55) No. 6 — Chassis ground:
4 CHECK LOCK-UP DUTY SOLENOID.
Measure the resistance between transmission
connector receptacle's terminals.
Connector & terminal
(T4) No. 12 — No. 20:
5 CHECK OUTPUT SIGNAL OF TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Lift up the vehicle.
3) Connect the Subaru Select Monitor to data
link connector.
4) Start the engine.
5) Run the Subaru Select Monitor.
NOTE:
If the ambient temperature is below 0°C (32°F),
drive the vehicle until the ATF reaches its oper-
ating temperature.
6) Read the data of "Lock Up Duty Ratio" using
Subaru Select Monitor.
7) Shift the select lever to "D" range, and slowly
increase vehicle speed to 60 km/h (37 MPH).
NOTE:
The speed difference between front and rear
wheels lights the ABS warning light or the VDC
warning light, but this does not indicate a mal-
function. If the warning light is illuminated, clear
the memory of ABS or VDC after completing AT
control diagnosis. <Ref. to ABS(diag)-21, Clear
Memory Mode.> <Ref. to VDC(diag)-24, Clear
Memory Mode.>
Check
Are DTCs other than P0743
displayed?
Is the resistance less than 1 ? Go to step 3.
Is the resistance 1 M or
more?
Is the resistance 2.0 — 6.0 ? Go to step 5.
Is the measured value 95%?
4AT(diag)-54
Yes No
Perform the diag- Go to step 2.
nosis according to
DTC.
Repair the open
circuit of harness
between TCM and
transmission con-
nector.
Go to step 4. Repair the short
circuit of harness
between TCM and
transmission con-
nector.
Go to step 8.
Go to step 6. Go to step 7.