SUBARU LEGACY 1997 Service Repair Manual

B2M0481
10D2CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn ignition switch to OFF and Subaru Select Monitor
or the OBD-II general scan tool switch to OFF.
2) Disconnect connector from mass air flow sensor.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Read data on Subaru select monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F06
: Is the value more than 250 g/sec or5Vin
function mode F06?
: Repair battery short circuit in harness between
mass air flow sensor and ECM connector. After
repair, replace ECM.
: Replace mass air flow sensor.

OBD-II general scan tool
For detailed operation procedures, refer to OBD-II General
Scan Tool Instruction Manual.
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B2M1062
E: DTC P0106
—PRESSURE SENSOR CIRCUIT
RANGE/PERFORMANCE PROBLEM—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1308
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

141
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10. Diagnostic Chart with Trouble Code for LHD Vehicles

10E1CHECK DTC P0107, P0108, P1102 OR
P1122 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0107,
P0108, P1102 OR P1122?
: Inspect DTC P0107, P0108, P1102 OR P1122
using“10. Diagnostics Chart with Trouble Code”.

NOTE:
In this case, it is not necessary to inspect DTC P0106.
: Go to step10E2.
OBD0145A
10E2
CHECK DATA FOR CONTROL.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch ON and Subaru Select Monitor or
the OBD-II general scan tool switch ON.
4) Start engine.
B2M0756
5) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21 and F20

F21: Display shows pressure signal value sent from the
pressure sensor.

F20: Display shows pressure signal value sent from the
pressure sensor.
: Is the value more than 85 kPa in function
mode F21?
: Go to step10E3.
: Go to next.
142
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0755
: Is the value less than 32 kPa in function
mode F20?
: Go to step10E4.
: Go to next.
B2M0755
: Is the value more than 133 kPa in function
mode F20?
: Replace pressure sensor.
: Repair poor contact in pressure sensor connector,
pressure sources switching solenoid valve
connector, and ECM connector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M1063A
B2M1269A
B2M1270A
10E3
CHECK VACUUM HOSE.
: Is there a fault in vacuum hose?
NOTE:
Check the following items.

Disconnection of the vacuum hose from pressure
sources switching solenoid valve to intake manifold

Holes in the vacuum hose between pressure sources
switching solenoid valve to intake manifold

Clogging of the vacuum hose between pressure sources
switching solenoid valve to intake manifold

Disconnection of the vacuum hose from pressure sensor
to pressure sources switching solenoid valve

Holes in the vacuum hose between pressure sensor and
pressure sources switching solenoid valve

Clogging of the vacuum hose between pressure sensor
and pressure sources switching solenoid valve

Clogging of the filter
: Repair or replace hoses or filter.
: Go to step10E4.
143
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OBD0005B
10E4CHECK PRESSURE SOURCES SWITCH-
ING SOLENOID VALVE.
1) Turn ignition switch to OFF.
2) Connect test mode connector.
3) Turn ignition switch to ON.
: Does pressure sources switching solenoid
valve produce operating sound? (ON↔
OFF each 1.5 sec.)
NOTE:
Pressure sources switching solenoid valve operation check
can also be executed using Subaru Select Monitor (Func-
tion mode: FD10). For the procedure, refer to“COMPUL-
SORY VALVE OPERATION CHECK MODE”. [T3F0].>
: Replace pressure sensor.
: Replace pressure sources switching solenoid
valve.
144
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10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1064
F: DTC P0107
—PRESSURE SENSOR CIRCUIT LOW
INPUT—
DTC DETECTING CONDITION:

Immediately at fault recognition
WIRING DIAGRAM:
B2M1308
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

145
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0145A
10F1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Start engine.
B2M0756
5) Read the data on Subaru Select Monitor or the OBD-II
general scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21

F21: Display shows pressure signal value sent from
pressure sensor.
: Is the value less than 0 kPa in function
mode F21?
: Go to step10F2.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M0535A
10F2CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 21 (+)—Chassis ground ():
Is the voltage more than 4.5 V?
: Go to next step 2).
: Go to next.
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B2M0535A
: 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.
B2M0536A
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 26 (+)—Chassis ground ():
Is the voltage less than 0.2 V?
: Go to step10F3.
: Go to next step 3).
B2M0755
3) Read data on Subaru Select Monitor.

Subaru Select Monitor
Designate mode using function key.
Function mode: F20

F20: Display shows pressure signal value sent from
pressure sensor.
: Does the value change more than 0 kPa by
shaking harness and connector of ECM
while monitoring the value with Subaru
select monitor?
: Repair poor contact in ECM connector.
: Go to step10F3.
OBD0693A
10F3CHECK HARNESS BETWEEN ECM AND
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from pressure sensor.
3) Turn ignition switch to ON.
4) Measure voltage between pressure sensor connector
and engine ground.
147
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: Connector & terminal
(B2) No. 3 (+)—Engine ground ():
Is the voltage more than 4.5 V?
: Go to next step 5).
: Repair open circuit in harness between ECM and
pressure sensor connector.
B2M1065A
5) Turn ignition switch to OFF.
6) Disconnect connector from ECM.
7) Measure resistance of harness between ECM and pres-
sure sensor connector.
: Connector & terminal
(B84) No. 20—(B2) No. 1:
Is the resistance less than 1Ω?
: Go to next step 8).
: Repair open circuit in harness between ECM and
pressure sensor connector.
OBD0695A
8) Measure resistance of harness between pressure sen-
sor connector and engine ground.
: Connector & terminal
(B2) No. 2—Engine ground:
Is the resistance more than 500 kΩ?
: Go to next.
: Repair ground short circuit in harness between
ECM and pressure sensor connector.
: Is there poor contact in pressure sensor
connector?
: Repair poor contact in pressure sensor connector.
: Replace pressure sensor.
148
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10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1066
G: DTC P0108
—PRESSURE SENSOR CIRCUIT HIGH
INPUT—
DTC DETECTING CONDITION:

Immediately at fault recognition
WIRING DIAGRAM:
B2M1308
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

149
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles