1995 SUBARU LEGACY engine

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.
160
2-7ON-BOARD DIAGNOSTICS II SYSTEM
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

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
2-7ON-BOARD DIAGNOSTICS II SYSTEM
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
167
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0191
I: DTC P0125
—INSUFFICIENT COOLANT TEMPERATURE
FOR CLOSED LOOP FUEL CONTROL
(TW
—CL)—
DESCRIPTION:
Refer to“F: DTC P0115—ENGINE COOLANT TEM-
PERATURE SENSOR CIRCUIT MALFUNCTION—
[T11F0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine would not return to idling.
169
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1.Check DTC P0115 on display.
No
Ye s

Inspect DTC P0115 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0125.
Replace engine coolant temperature sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:
OBD0174

170
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD model
B2M0450
1CHECK FOR OTHER CAUSES AFFECTING
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 step 2.
174
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code