Subaru LEGACY 2004 Service Manual page 736

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OPTION CODE.
2 CHECK ANY OTHER DTC ON DISPLAY.
3 CHECK ENGINE COOLING SYSTEM.
NOTE:
Check the following items.
• Thermostat open stuck
• Coolant level
• Coolant freeze
• Tire diameter
Check
Is the option code EC, EK or
K4?
Is any other DTC displayed?
Is there any fault in engine
cooling system?
EN(H4SO 2.5)(diag)-120
Yes
Go to step 2. Refer to EN(H4SO
2.0) section. <Ref.
to EN(H4SO
2.0)(diag)-66, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.
Inspect the rele- Go to step 3.
vant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4SO
2.5)(diag)-70, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0125.
Replace the ther- Replace the
mostat. <Ref. to engine coolant
CO(H4SO 2.0)-18, temperature sen-
Thermostat.> sor. <Ref. to
FU(H4SO 2.5)-20,
Engine Coolant
Temperature Sen-
sor.>
No