Subaru Legacy 2003 Service Manual page 1916

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 13 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value?
2 CHECK CURRENT DATA.
1) Turn the ignition switch to OFF.
2) Repair the battery short circuit in harness
between ECM and rear oxygen sensor con-
nector.
3) Turn the ignition switch to ON.
4) Read the data of rear oxygen sensor heater
current using Subaru Select Monitor.
Does the measured value exceed the spec-
ified value?
NOTE:
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4DOSTC)-26, Subaru Select Monitor.>
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?
Value
8 V
7 A
There is poor contact.
EN(H4DOSTC)-77
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Go to step 3.
Replace the ECM. END
<Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>
Repair the poor END
contact in ECM
connector.
No