sensor SUBARU LEGACY 1996 Service Repair Manual

WIRING DIAGRAM:

RHD Model
B2M0785
10C1
CHECK DTC P0100 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0100?
: Inspect DTC P0100 using“10. Diagnostics Chart
with Trouble Code 2-7 [T1000]”.
NOTE:
In this case, it is not necessary to inspect DTC P0101.
: Replace mass air flow sensor.
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10. Diagnostics Chart with Trouble Code

OBD0154
D: DTC P0105
—PRESSURE SENSOR CIRCUIT
MALFUNCTION (P
—S)—
DTC DETECTING CONDITION:

Immediately at fault recognition
10D1Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.

10D2Check input signal for ECM. (Using voltage
meter and Subaru Select Monitor.)
10D3Check harness between ECM and pressure
sensor connector.
10D4Check harness between ECM and pressure
sensor connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.



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10. Diagnostics Chart with Trouble Code

OBD0145A
10D1CONNECT 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 step10D2.
: Go to next.
B2M0756
: Is the value more than 140 kPa in function
mode F21?
: Go to step10D4.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open or short circuit in harness between pressure sen-
sor and ECM connector

Poor contact in pressure sensor

Poor contact in ECM connector

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

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 step10D3.
OBD0693A
10D3CHECK 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.
: 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.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

B2M0537A
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. 26—(B2) No. 2:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between ECM and
pressure 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 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.
140
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10. Diagnostics Chart with Trouble Code

B2M0756
10D4CHECK HARNESS BETWEEN ECM AND
PRESSURE 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 pressure 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 the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21
: Is the value more than 140 kPa in function
mode F21?
: Repair short circuit in harness between ECM and
pressure sensor connector.
: Replace pressure sensor.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
141
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10. Diagnostics Chart with Trouble Code

B2M0654
E: DTC P0106
—PRESSURE SENSOR CIRCUIT
RANGE/PERFORMANCE PROBLEM (PS
—R)
—
DTC DETECTING CONDITION:

Two consecutive trips with fault
10E1Check DTC P0105 or P1102 on display.
10E2Check data for control.
10E3Check vacuum hose.
10E4Check pressure sources switching solenoid
valve.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.




142
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10. Diagnostics Chart with Trouble Code

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.
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.
145
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10. Diagnostics Chart with Trouble Code

B2M0711A
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.
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”2-7 [T3F0].
: Replace pressure sensor.
: Replace pressure sources switching solenoid
valve.
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10. Diagnostics Chart with Trouble Code

OBD0172
F: DTC P0115
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (TW)—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
10F1Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.

10F2Check harness between engine coolant
temperature sensor and ECM connector.
10F3Check harness between engine coolant
temperature sensor and ECM connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

WIRING DIAGRAM:
B2M0539

147
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code