Subaru 2002 IMPREZA Service Manual page 1689

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from TCM and
transmission.
3)Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B55) No. 24 — (B11) No. 19:
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B54) No. 19 — (B11) No. 20:
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 24 — Chassis ground:
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B54) No. 19 — Chassis ground:
5 CHECK REAR VEHICLE SPEED SENSOR.
Measure the resistance between transmission
connector receptacle's terminals.
Connector & terminal
(T4) No. 19 — No. 20:
6 PREPARE OSCILLOSCOPE.
7 PREPARE SUBARU SELECT MONITOR.
8 CHECK INPUT SIGNAL FOR TCM.
1)Connect the connectors to TCM and trans-
mission.
2)Lift-up or raise the vehicle and place safety
stands.
NOTE:
On AWD models, raise all wheels off floor.
3)Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
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.>
4)Measure the voltage between TCM connec-
tor terminals.
Connector & terminal
(B55) No. 24 (+) — (B54) No. 19 ( − − − − ):
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Check
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the resistance more than 1
MΩ?
Is the resistance between 450
and 650 Ω?
Do you have an oscilloscope? Go to step 10.
Do you have a Subaru Select
Monitor?
Is the voltage more than AC 1
V?
AT-103
Yes
Go to step 2. Repair the open
circuit in harness
between TCM and
transmission con-
nector.
Go to step 3. Repair the open
circuit in harness
between TCM and
transmission, and
poor contact in
coupling connec-
tor.
Go to step 4. Repair the short
circuit in harness
between TCM and
transmission con-
nector.
Go to step 5. Repair the short
circuit in harness
between TCM and
transmission con-
nector.
Go to step 6. Replace the rear
vehicle speed sen-
sor. <Ref. to AT-
36, Rear Vehicle
Speed Sensor.>
Go to step 7.
Go to step 9. Go to step 8.
Even if the Go to step 11.
POWER indicator
lights up, the cir-
cuit has returned
to a normal condi-
tion at this time. A
temporary poor
contact of the con-
nector or harness
may be the cause.
Repair the har-
ness or connector
in TCM and trans-
mission.
No