Subaru Impreza 2003 Service Manual page 1758

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
5 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1)Turn the ignition switch OFF.
2)Lift-up the vehicle and place safety stand.
NOTE:
Raise all wheels off ground.
3)Start the engine, and warm transmission
until ATF temperature becomes 80°C (176°F)
or more.
NOTE:
It ambient temperature is below 0°C (32°F),
drive the vehicle until ATF reaches its operating
temperature.
4)Move the select lever to SPORT shift mode.
5)Increase the speed up to 25 km/h (16 MPH)
at 2nd.
NOTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-22, Clear Memory
Mode.>
6)Shift down to 1st speed, and effectively use
engine brake.
7)Measure the voltage between TCM connec-
tor and body ground when engine brake is
effective.
Connector & terminal
(B54) No. 14 (+) — Chassis ground ( − − − − ):
6 CHECK POOR CONTACT.
7 CHECK SHIFT SOLENOID 1 (IN TRANSMIS-
SION).
1)Remove the transmission connector from
bracket.
2)Lift-up or raise the vehicle and support with
safety stand.
3)Drain the automatic transmission fluid.
CAUTION:
Do not drain the automatic transmission flu-
id until it cools down.
4)Remove the oil pan, and disconnect the con-
nector from SPORT shift solenoid.
5)Measure the resistance between SPORT
shift solenoid connector and transmission
ground.
Terminals
No. 1 — Transmission ground:
Check
Is the voltage less than 1 V?
Is there poor contact in
SPORT shift solenoid circuit?
Is the resistance 10 — 16 Ω?
4AT-88
Yes
Even if "POWER" Go to step 6.
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
contact in the
TCM.
Repair the poor Replace the TCM.
contact. <Ref. to 4AT-70,
Transmission Con-
trol Module
(TCM).>
Go to step 8. Replace the
SPORT shift sole-
noid. <Ref. to 4AT-
64, Shift Sole-
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
No