Subaru 2003 LEGACY Service Manual page 73

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure resistance of harness between TCM
connector and chassis ground.
Connector & terminal
(B54) No. 1 — Chassis ground:
Is the measured value less than the specified
value?
4 PREPARE SUBARU SELECT MONITOR.
Do you have a Subaru Select Monitor?
5 CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and ECM.
2) Start the engine, and warm-up the trans-
mission until ATF temperature is above
80°C (176°F).
NOTE:
If ambient temperature is below 0°C (32°F),
drive the vehicle until the ATF reaches its oper-
ating temperature.
3) Engine idling.
4) Measure voltage between TCM connector
and chassis ground.
Connector & terminal
(B54) No. 1 (+) — Chassis ground ( − − − − ):
Is the measured value within the specified
range?
6 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 intake manifold pressure sig-
nal using Subaru Select Monitor.
•Display shows intake manifold pressure signal
value sent from ECM.
Is intake manifold pressure data within the
specified range?
7 CHECK POOR CONTACT.
Is there poor contact in intake manifold pres-
sure signal circuit?
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Value
1 MΩ
Subaru Select Monitor is avail-
able.
0.4 — 1.6 V
0.4 — 1.6 V
There is poor contact.
AT-71
Yes
Go to step 4. Repair short circuit
in harness
between TCM and
ECM connector.
Go to step 6. Go to step 5.
Even if "POWER" Go to step 7.
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 7.
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- Replace TCM.
tact. <Ref. to AT-76,
Transmission Con-
trol Module
(TCM).>
No