Subaru 2009 IMPREZA Service Manual page 560

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
Measure the resistance between engine cool-
ant temperature sensor terminals when the
engine coolant is cold and after warmed-up.
Terminals
No. 1 — No. 2:
Check
Is the resistance of engine cool-
ant temperature sensor differ-
ent between when engine
coolant is cold and after
warmed-up?
EN(H4SO)(diag)-143
ENGINE (DIAGNOSTICS)
Yes No
Repair the poor Replace the
contact of the ECM engine coolant
connector. temperature sen-
sor. <Ref. to
FU(H4SO)-25,
Engine Coolant
Temperature Sen-
sor.>