sensor SUBARU LEGACY 1997 Service Repair Manual

B2M1071
L: DTC P0123
—THROTTLE POSITION SENSOR CIRCUIT
HIGH INPUT—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
WIRING DIAGRAM:
B2M0540
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

167
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OBD0145A
10L1CONNECT 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.
B2M0482
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F07

F07: Throttle position sensor output signal is indicated.
: Is the value more than 4.9 V in function
mode F07?
: Go to step10L2.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. A temporary poor
contact of the connector may be the cause.
NOTE:
In this case, repair the following:

Poor contact in throttle position sensor connector

Poor contact in ECM connector

Poor contact in coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
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OBD0703A
10L2CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND BODY CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from throttle position sensor.
3) Measure resistance of harness between throttle posi-
tion sensor connector and engine ground.
: Connector & terminal
(E13) No. 1—Engine ground:
Is the resistance less than 5Ω?
: Go to next step 4).
: Repair open circuit in harness between throttle
position sensor and ECM connector.
OBD0704A
4) Turn ignition switch to ON.
5) Measure voltage between throttle position sensor con-
nector and engine ground.
: Connector & terminal
(E13) No. 2 (+)—Engine ground ():
Is the voltage more than 4.9 V?
: Repair battery short circuit in harness between
throttle position sensor and ECM connector. After
repair, replace ECM.
: Replace throttle position sensor.
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10M1CHECK DTC P0116 OR P0117 ON DIS-
PLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0116 or
P0117?
: Inspect DTC P0116 or P0117 using“10. Diagnos-
tics Chart with Trouble Code”. [T10A0].>
NOTE:
In this case, it is not necessary to inspect DTC P0125.
: Replace engine coolant temperature sensor.
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OBD0199
N: DTC P0130
—FRONT OXYGEN SENSOR CIRCUIT
MALFUNCTION—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1072
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

172
2-7ON-BOARD DIAGNOSTICS II SYSTEM
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10N1CHECK FOR OTHER CAUSES AFFECT-
ING EXHAUST GAS.
: Is CO % more than 2 % after engine warm-
up?
: Check fuel system.
NOTE:

Check for use of improper fuel.

Check if engine oil or coolant level is extremely low.
: Go to step10N2.
OBD0145A
10N2
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.
B2M0487
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: F12

F12: Front oxygen sensor max. and min. output signals
are indicated at the same time.
: Is the difference of voltage less than 0.1 V
between the value of max. output and min.
output with function mode F12?
: Go to step10N3.
: 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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B2M1073A
10N3CHECK HARNESS BETWEEN FRONT
OXYGEN SENSOR AND ECM CONNEC-
TOR.
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 engine ground.
: Connector & terminal
(B18) No. 3 (+)—Engine ground ():
Is the voltage more than 0.2 V?
: Go to next.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and front oxygen
sensor connector

Poor contact in the ECM connector
: 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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OBD0209
O: DTC P0133
—FRONT OXYGEN SENSOR CIRCUIT SLOW
RESPONSE—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1072
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

175
2-7ON-BOARD DIAGNOSTICS II SYSTEM
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10O1
CHECK DTC P0130 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0130?
: Inspect DTC P0130 using“10. Diagnostics Chart
with Trouble Code”.
NOTE:
In this case, it is not necessary to inspect DTC P0133.
: Go to step10O2.
10O2
CHECK EXHAUST SYSTEM.
: Is there a fault in exhaust system?
NOTE:
Check the following items.

Loose installation of front portion of exhaust pipe onto
cylinder heads

Loose connection between front exhaust pipe and front
catalytic converter

Damage of exhaust pipe resulting in a hole
: Repair exhaust system.
: Replace front oxygen sensor.
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OBD0212
P: DTC P0135
—FRONT OXYGEN SENSOR HEATER
CIRCUIT MALFUNCTION—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1074
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

177
2-7ON-BOARD DIAGNOSTICS II SYSTEM
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