Subaru IMPREZA 2002 Service Manual page 199

I
DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
IO
CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1)Connect the connectors to TCM and trans-
mission.
2)Lift-up or raise the vehicle and place safety
stands.
CAUTION:
Raise all wheels off floor.
3)Set the oscilloscope to TCM connector ter-
minals.
Turbo model
Positive probe; (655) No. 24
Earth lead; (855)
No.
19
Non-turbo model
Positive probe; (B55) No. 3
Earth lead; (B55) No. 21
4)Start the engine and set the vehicle in 20 km,
h (12 MPH) condition.
NOTE:
The speed difference between front and real
wheels may light the ABS warning light, but this
indicates no malfunction. When the AT contro
diagnosis is finished, perform the ABS memoq
clearance procedure of on-board diagnostic:
system. <Ref. to ABS-22, Clear Memoq
Mode.>
5)Measure the signal voltage indicated on
oscilbscope.
I1 CHECK POOR CONTACT.
Check
s the signal voltage more than
4 c
1 V?
s there poor contact in rear
iehicle speed sensor circuit?
~ ~
Yes
Even if the AT OIL
rEMP warning
ights up, the cir-
:uit has returned
o a normal condi-
ion at this time. A
emporary poor
:ontact of the con-
lector or harness
nay be the cause.
3epair harness or
:onnector in the
TCM and trans-
nission.
3epair poor con-
act.
No
30 to step 11.
3eplace the TCM.
:Ref. to AT-45,
rransmission Con-
rol Module
'TCM). >
AT-1 07