1997 SUBARU LEGACY service

B2M0541A
10K2CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Measure voltage between ECM connector and chassis
ground while throttle valve is fully closed.
: Connector & terminal
(B84) No. 21 (+)—Chassis ground ():
Is the voltage more than 4.5 V?
: Go to next step 2).
: Go to next.
: Does the voltage change more than 4.5 V by
shaking harness and connector of ECM
while monitoring the value with voltage
meter?
: Repair poor contact in ECM connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
B2M0542A
2) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 6 (+)—Chassis ground ():
Is the voltage less than 0.1 V?
: Go to step10K3.
: Go to next.
B2M0482
: Does the voltage change more than 0.1 V by
shaking harness and connector of ECM
while monitoring the value with Subaru
select monitor?
: Repair poor contact in ECM connector.
: Go to step10K3.
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B2M0481
7) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F06

F06: Mass air flow and voltage input from mass air flow
sensor are shown on display.
: Is the voltage in function mode F06 within
the specifications shown in the following
table?
Model Engine speed Specified value
2200 ccIdling 1.7—3.3 (g/sec)
2,500 rpm 7.1—14.2 (g/sec)
2500 ccIdling 2.2—4.2 (g/sec)
2,500 rpm 8.6—14.5 (g/sec)
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
: Replace mass air flow sensor.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
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B2M0556A
10AA1
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM connector and chassis
ground on faulty cylinders.
: Connector & terminal
#1 (B84) No. 96 (+)—Chassis ground ():
#2 (B84) No. 70 (+)—Chassis ground ():
#3 (B84) No. 44 (+)—Chassis ground ():
#4 (B84) No. 16 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Go to next.
: Go to step10AA2.
: Is there poor contact in ECM connector?
: Repair poor contact in ECM connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
OBD0713A
10AA2CHECK HARNESS BETWEEN FUEL
INJECTOR AND ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from fuel injector on faulty cylin-
ders.
3) Measure voltage between ECM connector and engine
ground on faulty cylinders.
: Connector & terminal
#1 (E5) No. 1—Engine ground:
#2 (E16) No. 1—Engine ground:
#3 (E6) No. 1—Engine ground:
#4 (E17) No. 1—Engine ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
fuel injector and ECM connector.
: Go to next step 4).
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B2M0567A
4) Measure resistance of harness between ECM and EGR
solenoid valve connector.
: Connector & terminal
(B84) No. 71—(E18) No. 2:
Is the voltage less than 1Ω?
: Go to step10AP4.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between EGR solenoid valve
and ECM connector

Poor contact in coupling connector (B21)

Poor contact in EGR solenoid valve connector

Poor contact in ECM connector
OBD0327
10AP4
CHECK EGR SOLENOID VALVE.
Measure resistance between EGR solenoid valve termi-
nals.
: Terminals
No. 1—No. 2:
Is the resistance between 10 and 100Ω?
: Go to step10AP5.
: Replace EGR solenoid valve.
OBD0328A
10AP5CHECK POWER SUPPLY TO EGR SOLE-
NOID VALVE.
1) Turn ignition switch to ON.
2) Measure voltage between EGR solenoid valve and
engine ground.
: Connector & terminal
(E18) No. 1 (+)—Engine ground ():
Is the voltage more than 10 V?
: Go to next.
: Repair open circuit in harness between main relay
and EGR solenoid valve connector.
: Is there poor contact in EGR solenoid valve
connector?
: Repair poor contact in EGR solenoid valve con-
nector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
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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.
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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.
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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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OBD0338
10AT3CHECK PURGE CONTROL SOLENOID
VA LV E .
1) Remove purge control solenoid valve.
2) Measure resistance between purge control solenoid
valve terminals.
: Terminals
No. 1—No. 2:
Is the resistance between 10 and 100Ω?
: Go to step10AT4.
: Replace purge control solenoid valve.
OBD0339A
10AT4CHECK POWER SUPPLY TO PURGE
CONTROL SOLENOID VALVE.
1) Turn ignition switch to ON.
2) Measure voltage between purge control solenoid valve
and engine ground.
: Connector & terminal
(E4) No. 1 (+)—Engine ground ():
Is the voltage more than 10 V?
: Go to next.
: Repair open circuit in harness between main relay
and purge control solenoid valve connector.
: Is there poor contact in purge control sole-
noid valve connector?
: Repair poor contact in purge control solenoid
valve connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles