Subaru Legacy 2003 Service Manual page 887

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
1 CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove generator.
3) Disconnect connector from engine coolant
temperature sensor.
4) Measure voltage between engine coolant
temperature sensor connector and engine
ground.
Connector & terminal
(E8) No. 1 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
2 CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to ON.
2) Measure voltage between engine coolant
temperature sensor connector and engine
ground.
Connector & terminal
(E8) No. 1 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 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?
Step
EN(H4SOw/oOBD)-68
Value
10 V
10 V
4 V
Yes
Repair battery Go to step 2.
short circuit in har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.
Repair battery Go to step 3.
short circuit in har-
ness between
ECM and engine
coolant tempera-
ture sensor con-
nector.
Go to step 4. 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
(B21)
No