Subaru Impreza 2003 Service Manual page 2419

DIAGNOSTICS PROCEDURE WITHOUT DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK SPECIFICATIONS OF THE AB-
SCM&H/U.
Check the specifications of mark on
ABSCM&H/U.
CK: FWD AT
CL: FWD MT
CU: AWD AT
CV: AWD MT
CX: AWD MT (STi model)
CY: AWD MT (STi with Driver's control
center differential model)
2 CHECK GROUND SHORT OF HARNESS.
1)Turn the ignition switch to OFF.
2)Disconnect all connectors from TCM.
3)Disconnect the connector from ABSCM&
H/U.
4)Measure the resistance between
ABSCM&H/U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 3 — Chassis ground:
RHD: (F49) No. 3 — Chassis ground:
3 CHECK BATTERY SHORT OF HARNESS.
Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD: (B301) No. 3 (+) — Chassis ground
( − − − − ):
RHD: (F49) No. 3 (+) — Chassis ground
( − − − − ):
4 CHECK BATTERY SHORT OF HARNESS.
1)Turn the ignition switch to ON.
2)Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD: (B301) No. 3 (+) — Chassis ground
( − − − − ):
RHD: (F49) No. 3 (+) — Chassis ground
( − − − − ):
5 CHECK TCM.
1)Turn the ignition switch to OFF.
2)Connect all connectors to TCM.
3)Turn the ignition switch to ON.
4)Measure the voltage between TCM connec-
tor terminal and chassis ground.
Connector & terminal
(B55) No. 21 (+) — Chassis ground ( − − − − ):
6 CHECK AT.
7 CHECK OPEN CIRCUIT OF HARNESS.
Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD:
(B301) No. 3 (+) — Chassis ground ( − − − − ):
(B301) No. 31 (+) — Chassis ground ( − − − − ):
RHD:
(F49) No. 3 (+) — Chassis ground ( − − − − ):
(F49) No. 31 (+) — Chassis ground ( − − − − ):
8 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
Check
Specifications between vehi-
cle and ABSCM&H/U are
matched?
Is the resistance more than 1
MΩ?
Is the voltage less than 1 V?
Is the voltage less than 1 V?
Is the voltage 10 — 15 V?
Is the AT functioning normally? Replace the TCM. Repair the AT.
Is the voltage 10 — 15 V?
nectors between TCM and
ABSCM&H/U?
ABS-79
ABS (DIAGNOSTICS)
Yes
Go to step 2. Replace the
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
Go to step 3. Repair the har-
ness between
TCM and
ABSCM&H/U.
Go to step 4. Repair the har-
ness between
TCM and
ABSCM&H/U.
Go to step 5. Repair the har-
ness between
TCM and
ABSCM&H/U.
Go to step 7. Go to step 6.
Go to step 8. Repair the har-
ness/connector
between TCM and
ABSCM&H/U.
Repair the con- Go to step 9.
nector.
No