Subaru Legacy 2003 Service Manual page 523

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
4 CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
Measure voltage between engine coolant tem-
perature sensor connector and engine ground.
Connector & terminal
(E8) No. 1 (+) — Engine ground ( − − − − ):
Does the measured value exceed the specified
value?
5 CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Measure resistance of harness between
engine coolant temperature sensor connec-
tor and engine ground.
Connector & terminal
(E8) No. 2 — Engine ground:
Is the measured value less than the speci-
fied value?
Step
EN(H4SO)-126
Value
4 V
5 Ω
Yes
Go to step 5. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and engine
coolant tempera-
ture sensor con-
nector
• Poor contact in
engine coolant
temperature sen-
sor connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
• Poor contact in
joint connector
Replace engine Repair harness
coolant tempera- and connector.
ture sensor. <Ref.
NOTE:
to FU(H4SO)-26,
In this case, repair
Engine Coolant
the following:
Temperature Sen-
• Open circuit in
sor.>
harness between
ECM and engine
coolant tempera-
ture sensor con-
nector
• Poor contact in
engine coolant
temperature sen-
sor connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
• Poor contact in
joint connector
No