Subaru 2009 IMPREZA Service Manual page 2033

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
1 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. 16 — (B11) No. 18:
(B55) No. 27 — (B11) No. 14:
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and transmission connector.
Connector & terminal
(B55) No. 16 — Chassis ground:
(B55) No. 27 — Chassis ground:
3 CHECK FRONT VEHICLE SPEED SENSOR.
Measure the resistance between transmission
connector receptacle's terminals.
Connector & terminal
(T4) No. 14 — No. 18:
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect all connectors.
2) Connect the Subaru Select Monitor to data
link connector.
3) Lift up the vehicle.
4) Turn the ignition switch to ON.
5) Run the Subaru Select Monitor.
6) Start the engine.
7) Slowly increase the 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.>
8) Read the data of "Front Wheel Speed" using
Subaru Select Monitor. (Compare the speed-
ometer with Subaru Select Monitor indications.)
5 CHECK POOR CONTACT.
Check
Is the resistance less than 1 ? Go to step 2.
Is the resistance 1 M or
more?
Is the resistance 450 — 650 ? Go to step 4.
Does the speedometer indica-
tion increase as the Subaru
Select Monitor front wheel
speed data increases?
Is there poor contact of front
vehicle speed sensor circuit?
4AT(diag)-48
Yes No
Repair the open
circuit of harness
between TCM and
transmission con-
nector, and poor
contact of the con-
nector.
Go to step 3. Repair the short
circuit of harness
between TCM and
chassis ground,
and poor contact of
connector.
Replace the front
vehicle speed sen-
sor. <Ref. to 4AT-
51, Front Vehicle
Speed Sensor.>
Check the harness Go to step 5.
of the front vehicle
speed sensor cir-
cuit, and repair the
defective part.
Repair the poor Replace the TCM.
contact. <Ref. to 4AT-63,
Transmission Con-
trol Module
(TCM).>