Subaru Legacy 2003 Service Manual page 2394

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
10 CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Connect connectors to TCM and transmis-
sion.
2) Lift-up or raise the vehicle and place safety
stands.
NOTE:
Raise all wheels off floor.
3) Set oscilloscope to TCM connector termi-
nals.
Connector & terminal
Positive probe; (B55) No. 24
Ground; (B54) No. 19
4) 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.> or <Ref. to VDC-25, Clear Memory
Mode.>
5) Measure signal voltage indicated on oscillo-
scope.
Does signal voltage exceed the the speci-
fied value?
11 CHECK POOR CONTACT.
Is there poor contact in rear vehicle speed sen-
sor circuit?
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Value
AC 1 V
There is poor contact.
AT-119
Yes
Even if "POWER" Go to step 11.
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
harness or con-
nector in the TCM
and transmission.
Repair poor con- Replace TCM.
tact. <Ref. to AT-76,
Transmission Con-
trol Module
(TCM).>
No