2004 SUBARU FORESTER catalytic converter

EN(H4SO)-13
ENGINE (DIAGNOSTIC)
Electrical Component Location
EN-00162
(2)
(3) (1)
(4)
(1) Front oxygen (A/F) sensor (3) Front catalytic converter (4) Rear catalytic converter
(2) Rear oxygen sensor
EN-00014
(1)
EN-00163 (2)
EN-00016
(3)
EN-00164 (4)

EN(H4SO)-128
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>
N
OTE:
In this case, it is not
necessary to in-
spect DTC P0133.Go to step 2.
2 CHECK EXHAUST SYSTEM.
N
OTE:
Check the following items:
 Loose installation of front portion of exhaust
pipe onto cylinder heads
 Loose connection between front exhaust
pipe and front catalytic converter
 Damage of exhaust pipe resulting in a holeIs there a fault in exhaust sys-
tem?Repair exhaust
system.Replace the front
oxygen (A/F) sen-
sor. FU(H4SO)-40,
Front Oxygen (A/
F) Sensor.>

EN(H4SO)-165
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>
N
OTE:
In this case, it is not
necessary to in-
spect DTC P0420.Go to step 2.
2 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 converterIs there a fault in exhaust sys-
tem?Repair or replace
the exhaust sys-
tem. EX(H4SO)-2, Gen-
eral Description.>Go to step 3.
3 CHECK CATALYTIC CONVERTER.Is there damage at rear face or
front face of catalytic con-
ver ter?Replace catalytic
converter. EC(H4SO)-3,
Front Catalytic
Converter.>Go to step 4.
4 CHECK REAR OXYGEN SENSOR CIRCUIT
MALFUNCTION.
1) Disconnect the connector from rear oxygen
sensor and ECM.
2) Measure the resistance between rear oxy-
gen sensor connector and ECM connector.
Connector & terminal
(T6) No. 3 — (B135) No. 19:Is the resistance less than 1
Ω?Go to step 5.Repair battery
open circuit in har-
ness between
ECM and rear oxy-
gen sensor.
5 CHECK SHIELD WIRE.Is the shield wire opened? Repair the shield
wire.Contact the SUB-
ARU dealer.

EMISSION CONTROL
(AUX. EMISSION CONTROL DEVICE)
EC(H4DOTC)
Page
1. General Description ....................................................................................2
2. Front Catalytic Converter ............................................................................3
3. Rear Catalytic Converter .............................................................................4
4. Precatalytic Converter .................................................................................5
5. Canister .......................................................................................................6
6. Purge Control Solenoid Valve .....................................................................7
7. Two-way Valve ............................................................................................8

EC(H4DOTC)-3
EMISSION CONTROL (AUX. EMISSION CONTROL DEVICE)
Front Catalytic Converter
2. Front Catalytic Converter
A: REMOVAL
1) Remove the center exhaust pipe. EX(H4DOTC)-9, REMOVAL, Center Exhaust
Pipe.>
2) Separate the front catalytic converter from cen-
ter exhaust pipe. (2.0 L model)
 2.0 L model
 2.5 L model
B: INSTALLATION
NOTE:
Replace the gaskets with new ones.
Install in the reverse order of removal.
C: INSPECTION
1) Make sure there are no exhaust leaks from con-
nections and welds.
2) Make sure there are no holes or rusting.
(A) Front catalytic converter
(A) Front catalytic converter
(A)
EC-02010
EC-00001
(A)

EC(H4DOTC)-4
EMISSION CONTROL (AUX. EMISSION CONTROL DEVICE)
Rear Catalytic Converter
3. Rear Catalytic Converter
A: REMOVAL
1. 2.0 L MODEL
1) Remove the center exhaust pipe. EX(H4DOTC)-9, REMOVAL, Center Exhaust
Pipe.>
2) Separate the rear catalytic converter from front
center exhaust pipe.
2. 2.5 L MODEL
Remove the rear exhaust pipe. EX(H4DOTC)-14, REMOVAL, Rear Exhaust
Pipe.>
B: INSTALLATION
NOTE:
Replace the gaskets with new ones.
Install in the reverse order of removal.
C: INSPECTION
1) Make sure there are no exhaust leaks from con-
nections and welds.
2) Make sure there are no holes or rusting.
(A) Rear catalytic converter
(A) Rear catalytic converter
(A)
EC-02011
(A)
EC-00002

EC(H4DOTC)-5
EMISSION CONTROL (AUX. EMISSION CONTROL DEVICE)
Precatalytic Converter
4. Precatalytic Converter
A: REMOVAL
Precatalytic converter (A) is built in the joint pipe.
Refer to the removal of joint pipe for removal proce-
dure. Pipe.>
B: INSTALLATION
Refer to the installation of joint pipe for installation
procedure. TION, Joint Pipe.>
C: INSPECTION
1) Make sure there are no exhaust leaks from con-
nections and welds.
2) Make sure there are no holes or rusting.
(A)
EC-00077

EX(H4DOTC)-3
EXHAUST
General Description
(1) Gasket (12) Exhaust manifold upper cover
(LH)Tightening torque: N·m (kgf-m, ft-lb)
(2) Exhaust manifold upper cover
(RH)T1: 19 (1.9, 13.7)
(13) Exhaust manifold lower cover (LH)T2: 7.5 (0.8, 5.5)
(3) Exhaust manifold (RH) (14) GasketT3: 35 (3.6, 26.0)
(4) Exhaust manifold lower cover
(RH)(15) Turbocharger joint pipeT4: 40 (4, 28.9)
(16) GasketT5: INSTALLATION, Front Oxygen
(A/F) Sensor.> or FU(H4DOTC 2.5)-37,
INSTALLATION, Front Oxygen
(A/F) Sensor.> (5) Front exhaust pipe upper cover (17) Front oxygen (A/F) sensor
(6) Front exhaust pipe upper insulator
(RH)(18) Exhaust temperature sensor
(19) Precatalytic converter
(7) Gasket (20) Front exhaust pipe upper insulator
(LH)
(8) Front exhaust pipeT6: INSTALLATION, Exhaust
Temperature Sensor.> or to FU(H4DOTC 2.5)-40,
INSTALLATION, Exhaust
Temperature Sensor.> (9) Front exhaust pipe lower insulator
(RH)(21) Front exhaust pipe lower insulator
(LH)
(10) Front exhaust pipe lower cover (22) Exhaust manifold (LH)
(11) Gasket