Subaru Legacy 2002 Service Manual page 1869

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Automatic Transmission (Diagnostics)
No.
1 CHECK TROUBLE CODE.
2 CHECK HARNESS CONNECTOR
BETWEEN TCM AND VDCCM.
1) Turn ignition switch to OFF.
2) Disconnect connector from TCM and
VDCCM.
3) Measure resistance of harness between
TCM and VDCCM connector.
Connector & terminal
(B56) No. 18 — (F87) No. 81:
3 CHECK HARNESS CONNECTOR
BETWEEN TCM AND VDCCM.
Measure resistance of harness between TCM
and VDCCM connector.
Connector & terminal
(B56) No. 9 — (F87) No. 83:
4 CHECK HARNESS CONNECTOR
BETWEEN TCM AND VDCCM.
Measure resistance of harness between TCM
and VDCCM connector.
Connector & terminal
(B56) No. 18 — Chassis ground:
5 CHECK HARNESS CONNECTOR
BETWEEN TCM AND VDCCM.
Measure resistance of harness between TCM
and VDCCM connector.
Connector & terminal
(B56) No. 9 — Chassis ground:
6 PREPARE OSCILLOSCOPE.
7 CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and VDCCM.
2) Turn ignition switch to ON (engine OFF).
3) Measure voltage between TCM connector
and chassis ground.
Connector & terminal
(B56) No. 9 (+) — Chassis ground (−):
(B56) No. 18 (+) — Chassis ground (−):
8 CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Set oscilloscope to TCM connector termi-
nals.
Connector & terminal
Positive probe; (B56) No. 9
Ground; (B55) No. 9
2) Turn ignition switch to ON (engine OFF).
9 CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Set oscilloscope to TCM connector termi-
nals.
Connector & terminal
Positive probe; (B56) No. 18
Ground; (B55) No. 9
2) Turn ignition switch to ON (engine OFF).
Step
Do multiple trouble codes
appear in the on-board
diagnostics test mode?
Is the resistance less than
1 Ω?
Is the resistance less than
1 Ω?
Is the resistance less than
1 MΩ?
Is the resistance less than
1 MΩ?
Do you have oscilloscope?
Does input voltage value
change?
Check signal waveform
pattern on oscilloscope.
<Ref. AT-18, WAVEFORM,
MEASUREMENT, Trans-
mission Control Module
(TCM) I/O Signal.> Is
waveform pattern same as
that shown in the figure?
Check signal waveform
pattern on oscilloscope.
<Ref. AT-18, WAVEFORM,
MEASUREMENT, Trans-
mission Control Module
(TCM) I/O Signal.> Is
waveform pattern same as
that shown in the figure?
AT-100
Check Yes
Go to another
trouble code.
Go to step 3.
Go to step 4.
Go to step 5.
Go to step 6.
Go to step 8.
Go to step 10.
Go to step 9.
Go to step 10.
No
Go to step 2.
Repair open cir-
cuit in harness
between TCM and
VDCCM, and poor
contact in cou-
pling connector.
Repair open cir-
cuit in harness
between TCM and
VDCCM, and poor
contact in cou-
pling connector.
Repair short cir-
cuit in harness
between TCM and
VDCCM connec-
tor.
Repair short cir-
cuit in harness
between TCM and
VDCCM connec-
tor.
Go to step 7.
Repair poor con-
tact in VDCCM.
Repair poor con-
tact in VDCCM.
Repair poor con-
tact in VDCCM.