Subaru Legacy 2003 Service Manual page 666

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B137) No. 19 (+) — Chassis ground ( − − − − ):
Is the measured value less than the speci-
fied value?
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM and TCM.
3) Measure resistance of harness between
ECM and chassis ground.
Connector & terminal
(B137) No. 19 — Chassis ground:
Does the measured value exceed the spec-
ified value?
3 CHECK OUTPUT SIGNAL FOR ECM.
1) Connect connector to ECM.
2) Turn ignition switch to ON.
3) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B137) No. 19 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
4 CHECK TROUBLE CODE FOR AUTOMATIC
TRANSMISSION.
Read trouble code for automatic transmission.
<Ref. to AT-24, Read Diagnostic Trouble Code
(DTC).>
Does trouble code appear for automatic trans-
mission?
Value
1 V
1 MΩ
5 V
Trouble code indicated.
EN(H4SO)-269
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Even if MI lights
up, the circuit has
returned to a nor-
mal condition at
this time.
NOTE:
In this case, repair
the following:
• Poor contact in
ECM connector
• Poor contact in
TCM connector
Go to step 3. Repair ground
short circuit in har-
ness between
ECM and TCM
connector.
Go to step 4. Repair poor con-
tact in ECM con-
nector.
Inspect trouble Replace TCM.
code for auto- <Ref. to AT-76,
matic transmis- Transmission Con-
sion. <Ref. to AT- trol Module
42, Diagnostic (TCM).>
Procedure with
Diagnostic Trou-
ble Code (DTC).>
No