SUBARU LEGACY 1997 Service Repair Manual

OBD0329
AQ: DTC P0420
—CATALYST SYSTEM EFFICIENCY BELOW
THRESHOLD—
DTC DETECTING CONDITION:

Immediately at fault recognition (2200 cc Federal spec.
vehicles only)

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Engine stalls.

Idle mixture is out of specifications.
WIRING DIAGRAM:
B2M1097
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

240
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10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AQ1CHECK ANY OTHER DTC P0130, P0133,
P0135, P0136, P0139 AND P0141 ON DIS-
PLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0130,
P0133, P0135, P0136, P0139 and P0141?
: Inspect the relevant DTC using“10. Diagnostics
Chart with Trouble Code”.
NOTE:
In this case, it is not necessary to inspect DTC P0420.
: Go to step10AQ2.
10AQ2
CHECK EXHAUST SYSTEM.
Check for gas leaks or air suction caused by loose or dis-
located nuts and bolts, and open hole at exhaust pipes.
: Is there a fault in exhaust system?
NOTE:
Check the following positions.

Between cylinder head and front exhaust pipe

Between front exhaust pipe and front catalytic converter

Between front catalytic converter and rear catalytic con-
verter
: Repair or replace exhaust system.
: Go to step10AQ3.
OBD0525B
10AQ3
CHECK REAR CATALYTIC CONVERTER.
1) Separate rear catalytic converter from rear exhaust
pipe.
: Is there damage at rear face of rear cata-
lyst?
: Replace front and rear catalytic converters.
: Go to next step 2).
OBD0524B
2) Remove front catalytic converter.
: Is there damage at rear face or front face of
front catalyst?
: Replace front catalytic converter.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
241
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

H2M1365
AR: DTC P0440
—EVAPORATIVE EMISSION CONTROL
SYSTEM MALFUNCTION—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Gasoline smell
WIRING DIAGRAM:
B2M0919
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

242
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AR1CHECK ANY OTHER DTC (BESIDES DTC
P0440) ON DISPLAY.
: Is there any other DTC on display?
: Inspect the relevant DTC using“10. Diagnostics
Chart with Trouble Code”.
: Go to step10AR2.
10AR2CHECK FUEL FILLER CAP AND FUEL
FILLER PIPE.
1) Turn ignition switch to OFF.
2) Open the fuel flap.
: Is the fuel filler cap tightened securely?
: Tighten fuel filler cap securely.
: Go to next.
: Is there any damage to the seal between
fuel filler cap and fuel filler pipe?
: Repair or replace fuel filler cap and fuel filler pipe.
: Go to step10AR3.
OBD0005B
10AR3CHECK VENT CONTROL SOLENOID
VA LV E .
1) Connect test mode connector.
2) Turn ignition switch to ON.
B2M0925A
: Does vent control solenoid valve produce
operating sound?
NOTE:
Vent control solenoid valve operation check can also be
executed using Subaru Select Monitor (Function mode:
FD08). For the procedure, refer to“COMPULSORY VALVE
OPERATION CHECK MODE”.
: Go to step10AR4.
: Replace vent control solenoid valve.
243
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1039B
10AR4CHECK PURGE CONTROL SOLENOID
VA LV E .
: Does purge control solenoid valve produce
operating sound?
NOTE:
Purge control solenoid valve operation check can also be
executed using Subaru Select Monitor (Function mode:
FD02). For the procedure, refer to“COMPULSORY VALVE
OPERATION CHECK MODE”.
: Go to step10AR5.
: Replace purge control solenoid valve.
B2M0923B
10AR5CHECK PRESSURE CONTROL SOLE-
NOID VALVE.
: Does pressure control solenoid valve pro-
duce operating sound?
NOTE:
Pressure control solenoid valve operation check can also
be executed using Subaru Select Monitor (Function mode:
FD07). For the procedure, refer to“COMPULSORY VALVE
OPERATION CHECK MODE”.
: Go to step10AR6.
: Replace pressure control solenoid valve.
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10AR6CHECK EVAPORATIVE EMISSION CON-
TROL SYSTEM LINE.
Turn ignition switch to OFF.
: Does fuel leak in fuel line?
: Repair or replace fuel line.
: Go to next.
: Is there any damage at canister?
: Repair or replace canister.
: Go to next.
: Is there any damage at fuel tank?
: Repair or replace fuel tank.
: Go to next.
: Are there holes, cracks, clogging or discon-
nections of hoses or pipes in evaporative
emission control system?
: Repair or replace hoses or pipes.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
245
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0331
AS: DTC P0441
—EVAPORATIVE EMISSION CONTROL
SYSTEM INCORRECT PURGE FLOW—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1310
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

246
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AS1CHECK DTC P0106, P0107, P0108, P0443,
P1102, P1122 OR P1422 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0106,
P0107, P0108, P0443, P1102, P1122 or
P1422?
: Inspect the relevant DTC P0106, P0107, P0108,
P0443, P1102, P1122 or P1422 using“10. Diag-
nostics Chart with Trouble Code”. [T10A0].>
NOTE:
In this case, it is not necessary to inspect DTC P0441.
: Go to step10AS2.
OBD0005B
10AS2CHECK PURGE CONTROL SOLENOID
VALVE OPERATION.
1) Turn ignition switch to OFF.
2) Connect test mode connector at the lower portion of
instrument panel (on the driver’s side), to the side of the
center console box.
3) Turn ignition switch to ON.
: Does purge control solenoid valve produce
operating sound at about 0.3 Hz?
NOTE:
Purge control solenoid valve operation check can also be
executed using Subaru Select Monitor (Function mode:
FD02). For the procedure, refer to“COMPULSORY VALVE
OPERATION CHECK MODE”.
: Go to next step 4).
: Replace purge control solenoid valve.
4) Disconnect canister purge hose from canister.
: Does pulsation occur by blowing through
the canister purge hose?
: Repair or replace evaporation line.
NOTE:
In this case, repair the following:

Loose connections in evaporation line

Cracks in evaporation line

Clogging in evaporation line
: Replace purge control solenoid valve.
247
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0335
AT: DTC P0443
—EVAPORATIVE EMISSION CONTROL
SYSTEM PURGE CONTROL VALVE CIRCUIT
LOW INPUT—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Erroneous idling
WIRING DIAGRAM:
B2M1310
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

248
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0570A
10AT1
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 72 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. Contact with SOA
service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
: Go to step10AT2.
OBD0680A
10AT2CHECK HARNESS BETWEEN PURGE
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from purge control solenoid
valve and ECM.
3) Measure resistance of harness between purge control
solenoid valve connector and engine ground.
: Connector & terminal
(E4) No. 2—Engine ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and purge control solenoid valve connector.
: Go to next step 4).
B2M0571A
4) Measure resistance of harness between ECM and
purge control solenoid valve of harness connector.
: Connector & terminal
(B84) No. 72—(E4) No. 2:
Is the resistance less than 1Ω?
: Go to step10AT3.
: Repair open circuit in harness between ECM and
purge control solenoid valve connector.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles