SUBARU LEGACY 1995 Service Repair Manual

OBD0145A
2
CHECK FRONT OXYGEN SENSOR DATA.
1) Turn ignition switch to OFF.
2) Connect the Subaru Select Monitor or the OBD-II gen-
eral scan tool to data link connector.
3) Start engine and Turn the Subaru Select Monitor and
the OBD-II general scan tool switch to ON.
4) Warm-up the engine until coolant temperature is above
70°C (160°F) and keep the engine speed at 2,000 rpm to
3,000 rpm for one minute.
5) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.
OBD0206
OBD0207

Subaru Select Monitor
Designate mode using function key.
Function mode: F14 or F15

F14: Front oxygen sensor max. output signal is indi-
cated.

F15: Front oxygen sensor min. output signal is indi-
cated.
: Is the difference of voltage between F14 and
F15 0.1 V, or less?
: Go to step 3.
: Replace front oxygen 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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11. Diagnostics Chart with Trouble Code

OBD0705A
3
CHECK HARNESS CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from front oxygen sensor.
3) Turn ignition switch to ON.
4) Measure voltage between front oxygen sensor harness
connector and body.
: Connector & terminal
(B18) No. 4—Body/0.2 V, or more
: Repair harness and connector.
NOTE:
In this case, the following are the possible causes.

1Open circuit of harness between ECM and front oxygen
sensor.

2Poor contact in the ECM connector.
: Go to next.
: Is there poor contact in front oxygen sensor
connector?
: Repair poor contact in front oxygen sensor con-
nector.
: Replace front oxygen sensor.
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11. Diagnostics Chart with Trouble Code

OBD0209
K: DTC P0133
—FRONT OXYGEN SENSOR CIRCUIT SLOW
RESPONSE (FO2
—R)—
DESCRIPTION:
Refer to“J: DTC P0130—FRONT OXYGEN SENSOR
CIRCUIT MALFUNCTION—[T11J0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
1.Check DTC P0130 on display.
No
Ye s

Inspect DTC P0130 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0133.
2.Check exhaust system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. <Ref. to
[T3D0] and [T3E0].>

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11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

LHD model
OBD0201
178
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD model
B2M0450
2
CHECK EXHAUST SYSTEM.
: Check the following.

Looseness of installation portion of front
exhaust pipe onto cylinder heads

Loosened connection of front exhaust
pipe and front catalytic converter

Damage of exhaust pipe which make a
hole
: Repair exhaust system.
: Replace front oxygen sensor.
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11. Diagnostics Chart with Trouble Code

OBD0212
L: DTC P0135
—FRONT OXYGEN SENSOR HEATER
CIRCUIT MALFUNCTION (FO2H)—
DESCRIPTION:
Refer to“J: DTC P0130—FRONT OXYGEN SENSOR
CIRCUIT MALFUNCTION—[T11J0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
180
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11. Diagnostics Chart with Trouble Code

1.Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.
2.Check output signal from ECM. (Using voltage
meter.)
3.Check power supply to front oxygen sensor.
4.Check front oxygen sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. <Ref. to
[T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD model
OBD0201



181
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11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD model
B2M0462
182
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0145A
1CONNECT 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
OBD-II general scan tool switch to ON.
4) Start engine.
OBD0215
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F29

F29: Front oxygen sensor heater current is indicated.
: Is the reading of F29 0.2 A, or more?
: Go to step 2.
: Repair connector.
NOTE:
In this case, poor contact in front oxygen sensor connec-
tor and ECM connector can be the possible cause.

OBD-II scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0216A
2CHECK OUTPUT SIGNAL FROM ECM. (USING
VOLTAGE METER.)
1) Start and idle the engine.
2) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 44—Body/1.0 V, or less
: Go to step 3.
: Go to next.
: Is the voltage less than 1.0 V while shaking
harness and connector of ECM?
: Repair poor contact in ECM connector.
: Go to next step.
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11. Diagnostics Chart with Trouble Code

OBD0216A
3) Disconnect connector from front oxygen sensor.
4) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 44—Body/1.0 V, or less
: Replace ECM.
: Repair short circuit of harness between ECM and
front oxygen sensor connector. After repair short
circuit of harness, replace ECM.
OBD0667A
3CHECK POWER SUPPLY TO FRONT OXYGEN
SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from front oxygen sensor.
3) Turn ignition switch to ON.
4) Measure voltage between front oxygen sensor connec-
tor and body.
: Connector & terminal
(B18) No. 2—Body/10 V, or more
: Go to step 4.
: Repair power supply line.
NOTE:
In this case, repair poor contact in connector or open cir-
cuit of harness between main relay and front oxygen sen-
sor.
OBD0706
4
CHECK FRONT OXYGEN SENSOR.
1) Turn ignition switch to OFF.
2) Measure resistance between front oxygen sensor con-
nector terminals.
: Terminals
No. 1—No. 2/30Ω, or less
: Repair harness and connector.
NOTE:
In this case, repair the following:

1Open circuit of harness between the front oxygen sen-
sor connector and the ECM connector

2Poor contact in front oxygen sensor connector

3Poor contact in ECM connector
: Replace front oxygen sensor.
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11. Diagnostics Chart with Trouble Code