Subaru Legacy 2004 Service Manual page 924

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK OPTION CODE.
2 CHECK ANY OTHER DTC ON DISPLAY.
3 CHECK EXHAUST SYSTEM.
Check for gas leaks or air suction caused by
loose or dislocated nuts and bolts, and open
hole at exhaust pipes.
NOTE:
Check the following positions.
• Between cylinder head and front exhaust
pipe
• Between front exhaust pipe and front cata-
lytic converter
• Between front catalytic converter and rear
catalytic converter
4 CHECK REAR CATALYTIC CONVERTER.
Separate the rear catalytic converter from rear
exhaust pipe.
5 CHECK FRONT CATALYTIC CONVERTER.
Remove the front catalytic converter.
Check
Is the option code EC, EK or
K4?
Is any other DTC displayed?
Is there any fault in exhaust
system?
Is there damage at rear face of
rear catalyst?
Is there damage at rear face or
front face of front catalyst?
EN(H4SO 2.5)(diag)-165
ENGINE (DIAGNOSTICS)
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 in-
spect DTC P0420.
Repair or replace Go to step 4.
the exhaust sys-
tem. <Ref. to
EX(H4SO 2.0)-2,
General Descrip-
tion.>
Replace the front Go to step 5.
catalytic con-
verter. <Ref. to
EC(H4SO 2.0)-3,
Front Catalytic
Converter.> and
rear catalytic con-
verter <Ref. to
EC(H4SO 2.0)-4,
Rear Catalytic
Converter.>
Replace the front Contact Subaru
catalytic con- distributor service.
verter. <Ref. to
NOTE:
EC(H4SO 2.0)-3,
Inspection by DTM
Front Catalytic
is required,
Converter.>
cause
cause is deteriora-
tion of
parts.
No
be-
probable
multiple