Subaru Legacy 2003 Service Manual page 2318

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
1) Turn ignition switch to OFF.
2) Disconnect connectors from TCM and
ECM.
3) Measure resistance of harness between
TCM and ECM connector.
Connector & terminal
Except 3.0 L model and TURBO model:
(B55) No. 17 — (B135) No. 30:
3.0 L model and TURBO model:
(B55) No. 17 — (B136) No. 9:
Is the measured value less than the speci-
fied value?
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure resistance of harness between TCM
connector and chassis ground.
Connector & terminal
(B55) No. 17 — Chassis ground:
Does the measured value exceed the specified
value?
3 PREPARE SUBARU SELECT MONITOR.
Do you have a Subaru Select Monitor?
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and ECM.
2) Turn ignition switch to ON (engine OFF).
3) Measure voltage between TCM connector
and chassis ground.
Connector & terminal
(B55) No. 17 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
5 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect connectors to TCM and ECM.
2) Connect Subaru Select Monitor to data link
connector.
3) Start the engine, and turn Subaru Select
Monitor switch to ON.
4) Warm-up the engine until engine coolant
temperature is above 80°C (176°F).
5) Engine idling.
6) Read data of engine speed using Subaru
Select Monitor.
•Display shows engine speed signal value sent
from ECM.
Is the revolution value the same as the
tachometer reading shown on the combina-
tion meter?
6 CHECK POOR CONTACT.
Is there poor contact in engine speed signal
circuit?
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Value
1 Ω
1 MΩ
Subaru Select Monitor is avail-
able.
10.5 V
Tachometer and select monitor
value are the same.
There is poor contact.
AT-43
Yes
Go to step 2. Repair open circuit
in harness
between TCM and
ECM connector.
Go to step 3. Repair short circuit
in harness
between TCM and
ECM connector.
Go to step 5. Go to step 4.
Even if "POWER" Go to step 6.
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 ECM.
Even if "POWER" Go to step 6.
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 ECM.
Repair poor con- Go to step 7.
tact.
No