sensor SUBARU LEGACY 1995 Service Repair Manual

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.
OBD0176
OBD0177
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F05 or F06

F05: Water temperature is indicated in“°F”.

F06: Water temperature is indicated in“°C”.
:
Is the value greater than 300°F with func-
tion mode F05?

Is the value greater than 150°C with func-
tion mode F06?
: Go to step 2.
: Go to next.
:
Is the value less than 40°F with function
mode F05?

Is the value less than 40°C with function
mode F06?
: Go to step 3.
: Repair poor contact in connectors or harness.

Engine coolant temperature sensor connector

ECM connector

Coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0618A
2
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
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11. Diagnostics Chart with Trouble Code

OBD0145A
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
OBD0176
OBD0177
5) Turn ignition switch and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
6) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F05 or F06

F05: Water temperature is indicated in“°F”.

F06: Water temperature is indicated in“°C”.
:
Is the value less than40°F with function
mode F05?

Is the value less than40°C with function
mode F06?
: Replace engine coolant temperature sensor.
: Repair short circuit of harness between engine
coolant temperature sensor connector and ECM
connector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
159
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0618A
3
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
4) Turn ignition switch to ON.
OBD0696A
5) Measure voltage between engine coolant temperature
sensor and body.
: Connector & terminal
(E8) No. 1—Body/4 V, or more
: Repair open circuit of harness or poor contact in
ECM and engine coolant temperature sensor con-
nector.
: Go to the next step.
6) Turn ignition switch to OFF.
OBD0697A
7) Measure resistance of harness between engine coolant
temperature sensor connector and body.
: Connector & terminal
(E8) No. 2—Body/10Ω, or less
: Repair open circuit of harness or poor contact in
ECM and engine coolant temperature sensor con-
nector.
: Replace engine coolant temperature sensor.
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11. Diagnostics Chart with Trouble Code

OBD0181
G: DTC P0120
—THROTTLE POSITION SENSOR CIRCUIT
MALFUNCTION (THV)—
OBD0182A
DESCRIPTION:

A throttle position sensor is provided with a potentiom-
eter which is interlocked with the throttle valve shaft.

This throttle position sensor sends the ECM a potenti-
ometer output signal corresponding to the opening of the
throttle valve. When the level of this signal exceeds a pre-
determined value, the ECM interprets it as complete clo-
sure of the throttle valve and makes a control most suitable
for the engine operation with the throttle valve fully closed.
For correcting error of this signal, the ECM is provided with
a learning function.

Thus, the ECM precisely controls the air-fuel ratio dur-
ing acceleration and deceleration as well as engine idling.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
161
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1.Connect Subaru Select Monitor or OBD-II
general scan tool and read data.

2.Check input signal for ECM. (Using voltage
meter and Subaru select monitor.)
3.Check harness connector between ECM and
throttle position sensor.
4.Check harness connector between throttle
position sensor and body.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:
OBD0183


162
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.
OBD0185
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F10

F10: Throttle position sensor output signal is indicated.
: Is the voltage less than 0.1 V?
: Go to step 2.
: Go to next.
: Is the voltage more than 4.9 V?
: Go to step 4.
: 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. Check
and repair the following connectors.

Throttle position sensor connector.

ECM connector

Coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
163
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11. Diagnostics Chart with Trouble Code

OBD0700A
3CHECK HARNESS CONNECTOR BETWEEN
ECM AND THROTTLE POSITION SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from throttle position sensor.
3) Turn ignition switch to ON.
4) Measure voltage between throttle position sensor con-
nector and body.
: Connector & terminal
(E13) No. 3—Body/4.5 V, or more
: Repair harness and connector.
NOTE:
In this case, the possible causes are:

1Open circuit of the harness between connector (E13)
terminal No. 3 and connector (B84) terminal No. 22, or
the following:

2Poor contact in throttle position sensor connector

3Poor contact in ECM connector

4Poor contact in coupling connector (B21)
: Go to the next step.
OBD0701A
5) Turn ignition switch to OFF.
6) Measure resistance of harness between ECM connec-
tor and throttle position sensor connector.
: Connector & terminal
(B84) No. 24—(E13) No. 2/10Ω, or less
: Repair harness and connector.
NOTE:
In this case, the following are the possible causes.

1Open circuit between connector (B84) terminal No. 24
and connector (E13) terminal No. 2.

2Poor contact in ECM connector.

3Poor contact in throttle position sensor connector

4Poor contact in coupling connector (B21)
: Go to next step.
165
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11. Diagnostics Chart with Trouble Code

OBD0702A
7) Measure resistance of harness between throttle posi-
tion sensor connector and body.
: Connector & terminal
(E13) No. 2—Body/10Ω, or less
: Repair short circuit of harness between throttle
position sensor and ECM connector.
: Go to next.
: Is there poor contact in throttle position
sensor connector?
: Repair poor contact in throttle position sensor
connector.
: Replace throttle position sensor.
OBD0703A
4CHECK HARNESS CONNECTOR BETWEEN
THROTTLE POSITION SENSOR AND BODY.
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 body.
: Connector & terminal
(E13) No. 1—Body/10Ω, or less
: Repair open circuit of harness between throttle
position sensor and ECM connector.
: Go to the next step.
OBD0704A
4) Turn ignition switch to ON.
5) Measure voltage between throttle position sensor con-
nector and body.
: Connector & terminal
(E13) No. 2—Body/4.9 V, or more
: Repair short circuit of harness between throttle
position sensor and ECM connector.
: Replace throttle position sensor.
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11. Diagnostics Chart with Trouble Code

OBD0189
H: DTC P0121
—THROTTLE POSITION SENSOR CIRCUIT
RANGE/PERFORMANCE PROBLEM (TH
—R)
—
DESCRIPTION:
Refer to“G: DTC P0120—THROTTLE POSITION SEN-
SOR CIRCUIT MALFUNCTION—[T11G0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
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11. Diagnostics Chart with Trouble Code

Check DTC P0120 on display.
No
Ye s

Inspect DTC P0120 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0121.
Replace throttle position sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:
OBD0183

168
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code