SUBARU LEGACY 1995 Service Repair Manual

1CHECK SPEEDOMETER OPERATION IN COM-
BINATION METER.
: Check normal operation of speedometer.
: Check speedometer and vehicle speed sensor
.
: Go to step 2.
OBD0349A
2
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from TCM.
3) Turn ignition switch to ON.
4) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 57—Body / 2 V, or more
: Check the following and repair if necessary.

Open circuit of harness between ECM connector and
combination meter connector

Poor contact in ECM connector

Poor contact in combination meter connector

Poor contact in coupling connector (B37)
: Go to step 3.
OBD0351A
3
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between ECM connec-
tor and body.
: Connector & terminal
(B84) No. 57—Body / 10Ω, or less
: Repair short circuit of harness between ECM con-
nector and combination meter connector.
: Repair poor contact in ECM connector.
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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

1.Check air intake system.
2.Check output signal from ECM.

3.Check idle air control solenoid valve.
4.Check power supply to idle air control
solenoid valve.
5.Check harness connector between ECM and
idle air control solenoid valve.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD model
OBD0360




257
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11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD model
B2M0457
258
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11. Diagnostics Chart with Trouble Code

1
CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
3) Check intake manifold, idle air control solenoid valve
and throttle body for loose installation and gasket for
cracks.
4) Check by-pass hoses for loose connections and cracks.
5) Check vacuum hoses for disconnections.
OBD0362A
2
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 11—Body / 3 V, or more
(B84) No. 12—Body / 3 V, or more
: Go to step 4.
: Go to the next step.
OBD0362A
3) Turn ignition switch to OFF.
4) Disconnect connector from idle air control solenoid
valve.
5) Turn ignition switch to ON.
6) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 11—Body / 10 V, or more
(B84) No. 12—Body / 10 V, or more
: Repair short circuit of harness and replace ECM.
: Go to next.
: Is there poor contact in ECM connector?
: Repair poor contact in ECM connector.
: Go to step 3.
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11. Diagnostics Chart with Trouble Code

OBD0366
3CHECK IDLE AIR CONTROL SOLENOID
VA LV E .
1) Turn ignition switch to OFF.
2) Measure resistance between solenoid valve terminals.
: Terminals
No. 1—No. 2 / 20Ω, or more
No. 2—No. 3 / 20Ω, or more
: Replace idle air control solenoid valve.
: Go to next.
: Terminals
No. 1—No. 2 / 5Ω, or less
No. 2—No. 3 / 5Ω, or less
: Replace idle air control solenoid valve and ECM.
: Go to next step.
OBD0683
3) Remove idle air control solenoid valve. [W12A0].>
4) Check operation of idle air control solenoid valve.
: When connecting the battery to terminals
No. 1 and No. 2 of idle air control solenoid
valve, check if it is fully opened.
: Go to next.
: Clean idle air control solenoid valve. [W12B0].>
OBD0684
: When connecting the battery to terminals
No. 3 and No. 2 of idle air control solenoid
valve, check if it is fully closed.
: Go to step 4.
: Clean idle air control solenoid valve. [W12B0].>
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11. Diagnostics Chart with Trouble Code

B2M0253A
4CHECK POWER SUPPLY TO IDLE AIR CON-
TROL SOLENOID VALVE.
1) Turn ignition switch to OFF.
2) Disconnect connector from idle air control solenoid
valve.
3) Turn ignition switch to ON.
4) Measure voltage between idle air control solenoid valve
and body.
: Connector & terminal
(E7) No. 2—Body / 10 V, or more
: Go to step 5.
: Repair open circuit of harness between idle air
control solenoid valve connector and ECM con-
nector.
OBD0368A
5CHECK HARNESS CONNECTOR BETWEEN
ECM AND IDLE AIR CONTROL SOLENOID
VA LV E .
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness connector between
ECM and idle air control solenoid valve.
: Connector & terminal
(B84) No. 11—(E7) No. 3 / 10Ω, or less
(B84) No. 12—(E7) No. 1 / 10Ω, or less
: Repair open circuit of harness between ECM con-
nector and idle air control solenoid valve connec-
tor.
: Go to the next step.
OBD0369A
4) Measure resistance of harness connector between
ECM and body to make sure that circuit does not short.
: Connector & terminal
(B84) No. 11—Body / 1 MΩ, or more
(B84) No. 12—Body / 1 MΩ, or more
: Confirm good condition in connectors of idle air
control solenoid valve circuit.
: Repair short circuit of harness between ECM con-
nector and idle air control solenoid valve connec-
tor.
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11. Diagnostics Chart with Trouble Code

OBD0370
AI: DTC P0506
—IDLE CONTROL SYSTEM RPM LOWER
THAN EXPECTED (ISC
—L)—
DESCRIPTION:
Refer to“AH: DTC P0505—IDLE CONTROL SYSTEM
MALFUNCTION—[T11AH0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine is difficult to start.

Engine does not start.

Erroneous idling

Engine stalls.
1.Check DTC P0505 on display.
No
Ye s

Inspect DTC P0505 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0506.
2.Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

262
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11. Diagnostics Chart with Trouble Code

2
CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
: Is clogging the by-pass line between by-
pass hose and intake duct?
: Repair the by-pass line.
: Replace idle air control solenoid valve.
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11. Diagnostics Chart with Trouble Code

OBD0371
AJ: DTC P0507
—IDLE CONTROL SYSTEM RPM HIGHER
THAN EXPECTED (ISC
—H)—
DESCRIPTION:
Refer to“AH: DTC P0505—IDLE CONTROL SYSTEM
MALFUNCTION—[T11AH0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine keeps running at higher revolution than specified
idling revolution.
1.Check DTC P0505 on display.
No
Ye s

Inspect DTC P0505 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0507.
2.Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

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11. Diagnostics Chart with Trouble Code