coolant temperature SUBARU LEGACY 1995 Service Owner's Guide

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
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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

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.
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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

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.
175
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1
CHECK DTC P0130 ON DISPLAY.
: Check that Subaru Select Monitor or the
OBD-II general scan tool shows P0130.
: Go to step 2.
: Go to step 3.
2
CHECK FAILURE CAUSE OF P0130.
Perform the step 1 of DTC P0130.
: Is the failure cause of P0130 in the fuel sys-
tem?
: Check fuel system. In this case, inspection of
P0136 is not necessary.
: Go to step 3.
OBD0145A
3
CHECK REAR OXYGEN SENSOR DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or OBD-II general scan
tool to data link connector.
3) Start the engine, and turn Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Warm-up the engine until engine coolant temperature is
above 70°C (160°F), and keep the engine speed at 2,000
rpm to 3,000 rpm for two minutes.
OBD0225
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F16

F16: Rear oxygen sensor output signal is indicated.
: Is the indicated data fluctuate?
: Go to step 5.
: Go to next.
: Is the indicated data fixed at 0.3±0.1 V?
: Go to step 4.
: Replace rear oxygen sensor.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
188
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11. Diagnostics Chart with Trouble Code

OBD0240
P: DTC P0170
—FUEL TRIM MALFUNCTION (FUEL)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
1.Check exhaust system.
2.Check air intake system.
3.Check fuel pressure.
4.Check engine coolant temperature sensor.

5.Check mass air flow sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODE. [T3D0] and [T3E0].>




198
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11. Diagnostics Chart with Trouble Code

4CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
< REF. TO“F: DTC P0115 [T11F0].”>
1) Turn ignition switch to OFF.
OBD0145A
2) Connect the Subaru Select Monitor or the OBD-II gen-
eral scan tool to data link connector.
3) Start the engine and warm-up completely.
OBD0176
OBD0177
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: F05 or F06

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

F06: Water temperature is indicated in“°C”.
: Is temperature indicated on Subaru Select
Monitor (F05) greater than 140°F?
Is temperature indicated on Subaru Select
Monitor (F06) greater than 60°C?
: Go to step 5.
: Replace engine coolant temperature sensor.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
201
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11. Diagnostics Chart with Trouble Code

OBD0331
AE: DTC P0441
—EVAPORATIVE EMISSION CONTROL
SYSTEM INCORRECT PURGE FLOW
(CPC
—F)—
DESCRIPTION:

The evaporative emission control system is employed to
prevent evaporative fuel from being discharged into ambi-
ent atmosphere. This system includes a canister, purge
control solenoid valve, fuel cut valve, their connecting lines,
etc.

Gasoline vapor evaporated from the fuel tank is intro-
duced into the canister located in the engine compartment
through the evaporation line, and is absorbed on activated
carbon in it. A fuel cut valve is also incorporated on the tank
fuel line.

The purge control solenoid valve is controlled by the
ECM and provides optimal purge control according to the
engine coolant temperature, engine load and vehicle
speed.
OBD0332A
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11. Diagnostics Chart with Trouble Code

OBD0358
OBD0688A
AH: DTC P0505
—IDLE CONTROL SYSTEM MALFUNCTION
(ISC)—
DESCRIPTION:

Idle air control solenoid valve consists of an air cut valve,
duty control valve, intake air passage and a coolant pas-
sage.

Air cut valve contains a bimetallic substance which
responds to coolant temperature, and a duty control valve
which is operated by a signal sent from ECM.

When engine coolant temperature is low, air cut valve is
fully opened by the action of the bimetallic substance so
that the air flow required for low engine coolant tempera-
tures is maintained.

ECM controls duty control valve to bring the operating
engine speed as close to preset idle speed as possible.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Engine breathing
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11. Diagnostics Chart with Trouble Code