Subaru Legacy 2002 Service Manual page 1824

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect all connectors.
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
diagnosis is finished, perform the ABS
memory clearance procedure of on-board
diagnostics system. <Ref. to ABS-21, Clear
Memory Mode.>
4) Measure voltage between TCM connector
terminals.
Connector & terminal
(B55) No. 18 (+) — (B54) No. 10 (−):
9 CHECK FRONT VEHICLE SPEED SENSOR
USING OSCILLOSCOPE.
1) Connect all connectors.
2) Lift-up the vehicle and place safety stand.
NOTE:
On AWD models, raise all wheels off ground.
3) Set oscilloscope to TCM connector termi-
nals.
Connector & terminal
Positive probe; (B55) No. 18
Ground; (B54) No. 10
4) Start the engine, and drive the wheels
slowly.
NOTE:
The speed difference between front and rear
wheels may light the ABS warning light, but
this indicates no malfunctions. When AT con-
trol diagnosis is finished, perform the ABS
memory clearance procedure of self-diagnosis
system. <Ref. to ABS-21, Clear Memory
Mode.>
5) Measure signal voltage indicated on oscil-
loscope.
Step
Is the voltage more than
AC 1 V?
Is the voltage more than
AC 4 V?
AT-55
Automatic Transmission (Diagnostics)
Check Yes
Even if "POWER"
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tem-
porary poor con-
nector or harness
may be the case.
Repair harness or
connector in the
front vehicle
speed sensor cir-
cuit.
Even if "POWER"
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tem-
porary poor con-
nector or harness
may be the case.
Repair harness or
connector in the
front vehicle
speed sensor cir-
cuit.
No
Go to step 11.
Go to step 11.