1997 SUBARU LEGACY engine head

B6M0361A
22. Security System
A: REMOVAL AND INSTALLATION
1. STARTER INTERRUPT RELAY
NOTE:
The starter interrupt relay and headlight alarm relay use the
same parts and are mounted parallel to each other.
Therefore, before removal and installation, identify the
starter interrupt relay by the color of its wiring connection.

1) Remove instrument panel lower cover.
2) Disconnect connector of starter interrupt relay.
3) Remove starter interrupt relay.
4) Installation is in the reverse order of removal.
B6M0361A
2. HEADLIGHT ALARM RELAY
NOTE:
The headlight alarm relay and starter interrupt relay use the
same parts and are mounted parallel to each other.
Therefore, before removal and installation, identify the
headlight alarm relay by the color of its wiring connection.

1) Remove instrument panel lower cover.
2) Disconnect connector of headlight alarm relay.
3) Remove headlight alarm relay.
4) Installation is in the reverse order of removal.
B6M0363A
3. ENGINE HOOD SWITCH
1) Disconnect connector of engine hood switch from bot-
tom side of switch body.
2) Remove headlight (LH).
3) Remove attaching bolt, and then remove engine hood
switch.
4) Installation is in the reverse order of removal.
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22. Security System

B6M0375A
B: INSPECTION
1. STARTER INTERRUPT RELAY
1) Disconnect connector of starter interrupt relay.
2) Connect battery to terminal No.1 and ground terminal
No. 2.
3) Check continuity between terminals as indicated in
table below:
When current flows. Between terminals
No. 3 and No. 5Continuity does not
exist.
When current does not flow. Between terminals
No. 3 and No. 5Continuity exists.
Between terminals
No. 1 and No. 2Continuity exists.
G6M0134
2. HEADLIGHT ALARM RELAY
1) Disconnect connector of headlight alarm relay.
2) Connect battery to terminal No. 1 and ground terminal
No. 2.
3) Check continuity between terminals as indicated in
table below:
When current flows. Between terminals
No. 3 and No. 5Continuity does not
exist.
Between terminals
No. 3 and No. 4Continuity exists.
When current does not flow. Between terminals
No. 3 and No. 5Continuity exists.
Between terminals
No. 3 and No. 4Continuity does not
exist.
Between terminals
No. 1 and No. 2Continuity exists.
B6M0376
3. ENGINE HOOD SWITCH
1) Disconnect connector of engine hood switch.
2) Check continuity between terminals when push rod is
pushed in 1.5 mm (0.059 in) of its stroke.
Terminal
Switch position12
When push rod is
pushed in.
When push rod is
released.
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6-2SERVICE PROCEDURE
22. Security System

C: FUNCTION TEST
1. SECURITY SYSTEM OPERATION
1) Fully open all the door windows.
2) Turn the ignition switch to OFF and remove ignition key
from ignition switch.
3) Get out of the vehicle and lock the driver’s door using a
ignition key.
4) Check that the security indicator light illuminates.
5) When the security indicator light illuminates, wait for 30
seconds.
After 30 seconds, check that the light starts repeating 0.2
sec. ON and 2.4 sec. OFF sequence.
6) Unlock the driver’s door using the inside lock knob and
open the door.
Ensure that:
(1) the horn sounds and headlights flash intermittently
at 0.2 sec. ON and 0.6 sec. OFF. intervals, and
(2) the engine will not start even if the ignition switch
is turned to START.
7) Unlock the driver’s door one time using the ignition key.
Ensure the horn and headlights turn off.
8) Close and lock the driver’s door without using a ignition
key. (Set the inside lock knob to LOCK and then close the
door while lifting the outer handle).
Check that the security indicator light illuminates continu-
ously.
9) Within 30 seconds after the above step 8), unlock the
rear LH door using the inside lock knob and open the door.
Check that the security indicator light flashes at 0.5 sec.
intervals.
10) Close the rear LH door and lock the door using the
inside lock knob.
Check that the security indicator light illuminates continu-
ously.
11) Perform the above steps 9) and 10) on the rear RH
door and front RH door.
12) Within 30 seconds after above step 11) has been
finished, pull the engine hood opener lever and open the
engine hood.
Check that the security indicator light flashes at 0.5 sec.
intervals.
13) Close the engine hood completely.
Check that the security indicator light illuminates continu-
ously.
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6-2SERVICE PROCEDURE
22. Security System

6. Security System
A: ELECTRICAL COMPONENTS LOCATION
B6M0403A
1Security control module

2Security indicator light

3RH door key cylinder lock/unlock switch (built-in tamper
switch)

4Door switch

5Door lock/unlock switch

6Trunk lid key cylinder unlock switch (SEDAN) (built-in tamper
switch)

7Trunk lid switch (SEDAN)

8Rear gate key cylinder lock/unlock switch (WAGON)
9Rear gate switch (WAGON)

10LH door key cylinder lock/unlock switch (built-in tamper
switch)

11Starter interrupt relay

12Headlight alarm relay

13Ignition switch (ACC position)

14Engine hood switch

15Horn

16Headlight
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6-2DIAGNOSTICS
6. Security System

C: CONTROL MODULE I/O SIGNAL
B6M0405
Content Terminal No.Measuring conditions and I/O signals
(Ignition switch ACC position)
Door lock/unlock switch1
(INPUT)
Battery voltage is present when all doors and rear gate (WAGON) are locked.

“0”volt is present when one of the doors or rear gate (WAGON) is unlocked.
Key cylinder lock switch2
(INPUT)
“0”volt is present when key cylinder is turned to LOCK position.

Battery voltage is present when key cylinder is in positions other than LOCK.
Tamper switch3
(INPUT)
Battery voltage is present when key cylinder switch is installed to key cylinder.

“0”volt is present when key cylinder switch is removed from key cylinder.
Door switch4
(INPUT)
Battery voltage is present when all doors are closed.

“0”volt is present when one of the doors is open.
Starter interrupt relay5
(OUTPUT)
Battery voltage is present when ignition switch is turned ACC or ON.

“0”volt is present when security system is in alarm state.
Ignition switch (ACC)6
(INPUT)
Battery voltage is present when ignition switch is turned ACC or ON.

“0”volt is present when ignition switch is turned OFF.
Security indicator light7
(OUTPUT)
Battery voltage is present when indicator light goes off.

“0”volt is present when indicator light illuminates.
Power supply (back-up) 8 Battery voltage is constantly present.
Ground 9—
Engine hood switch10
(INPUT)
Battery voltage is present when engine hood is closed.

“0”volt is present when engine hood is open.
Trunk lid switch (SEDAN)
Rear gate switch (WAGON)11
(INPUT)
Battery voltage is present when trunk lid or rear gate is closed.

“0”volt is present when trunk lid or rear gate is open.
Headlight alarm relay12
(OUTPUT)
Battery voltage is present when ignition switch is turned ACC or ON.

“0”volt and battery voltage repeats in alarm state. (Headlights flash intermittently
at 0.2 sec. ON and 0.6 sec. OFF intervals).
Horn relay13
(OUTPUT)
Battery voltage is present when ignition switch is turned ACC or ON.

“0”volt and battery voltage repeats in alarm state. (Horn sounds intermittently at
0.2 sec. ON and 0.6 sec. OFF intervals.)
Key cylinder unlock switch14
(INPUT)
“0”volt is present when key cylinder is turned to UNLOCK position.

Battery voltage is present when key cylinder is in positions other than UNLOCK.
Trunk lid key cylinder unlock
switch (SEDAN)15
(INPUT)
“0”volt is present when trunk lid key cylinder is turned to UNLOCK position.

Battery voltage is present when trunk lid key cylinder is in positions other than
UNLOCK.
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6-2DIAGNOSTICS
6. Security System

D: BASIC DIAGNOSTICS PROCEDURE
Start security system check.
Fully open all door windows and turn ignition switch OFF.
Take key out of ignition, exit vehicle and lock driver’s door.
Indicator light illuminates.
OK The light flashes.
 The light does not
illuminate.
Check indicator harness.
Check security indicator light.
Check driver’s door key cylinder lock/unlock switch.
Check security control module.
Check whether switch input signal remains UNLOCK.
Check wiring harness.
Check switch input signals.
(Harnesses and switches separately)
(Tamper, door, hood, trunk and rear gate
switch)Check security control module.
Wait for 30 seconds.
Indicator light flashes at long intervals (0.2 sec. ON and 2.4 sec.
OFF).
OK
 Not OK
Check security control module.
Unlock driver’s door using the inside lock knob and open door.
The horn sounds and headlights flash intermittently at 0.2 sec. ON
and 0.6 sec. OFF intervals.
The engine will not start even if the ignition switch is turned to
START. Indicator lamp goes out.
OK Starter motor runs.
 All are not OK.
Check driver’s door switch.
Check wiring harness.
Check security control module.
 Horn is not OK.
Check horn
operation by
pushing horn pad
on steering wheel.
OK
 Not OK
Check horn.
Check horn relay.
Check security control module.
Check harness between horn relay and security control module.
 Headlights are not
OK.
Check headlights
operation by
turning light switch
ON/OFF.
OK
 Not OK
Check headlight
bulbs.
Check combination
switch.
Check headlight
relay.
Check starter interrupt relay.
Check wiring harness.
Check security control module.Check headlight alarm relay.
Check security control module.
Check wiring harness.
The alarm system continues to operate for 150 seconds.
OK Not OK
The horn and
headlights turn off.
The starter motor
does not run.
OK
 Not OK
Check security
control module.
Unlock the driver’s door using ignition key.
Continues to next step.














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6-2DIAGNOSTICS
6. Security System

1. General
1. GENERAL DESCRIPTION

The on-board diagnostics (OBD) system detects and
indicates a fault in various inputs and outputs of the com-
plex electronic control. CHECK ENGINE malfunction indi-
cator lamp (MIL) in the combination meter indicates occur-
rence of a fault or trouble.

Further, against such a failure or sensors as may disable
the drive, the fail-safe function is provided to ensure the
minimal driveability.

The OBD system incorporated with the vehicles within
this engine family complies with Section 1968.1, California
Code of Regulations (OBD-II regulation). The OBD system
monitors the components and the system malfunction
listed in Engine Section which affects on emissions.

When the system decides that a malfunction occurs, MIL
illuminates. At the same time of the MIL illumination or
blinking, a diagnostic trouble code (DTC) and a freeze
frame engine conditions are stored into on-board com-
puter.

The OBD system stores freeze frame engine condition
data (engine load, engine coolant temperature, fuel trim,
engine speed and vehicle speed, etc.) into on-board com-
puter when it detects a malfunction first.

If the OBD system detects the various malfunctions
including the fault of fuel trim or misfire, the OBD system
first stores freeze frame engine conditions about the fuel
trim or misfire.

When the malfunction does not occur again for three
consecutive driving cycles, MIL is turned off, but DTC
remains at on-board computer.

The OBD-II system is capable of communication with a
general scan tool (OBD-II general scan tool) formed by ISO
9141 CARB.

The OBD-II diagnostics procedure is different from the
usual diagnostics procedure. When troubleshooting OBD-II
vehicles, connect Subaru select monitor or the OBD-II gen-
eral scan tool to the vehicle.
A: ENGINE
1. ENGINE AND EMISSION CONTROL SYSTEM

The Multipoint Fuel Injection (MFI) system is a system
that supplies the optimum air-fuel mixture to the engine for
all the various operating conditions through the use of the
latest electronic technology.
With this system fuel, which is pressurized at a constant
pressure, is injected into the intake air passage of the cyl-
inder head. The injection quantity of fuel is controlled by an
intermittent injection system where the electro-magnetic
injection valve (fuel injector) opens only for a short period
of time, depending on the quantity of air required for one
cycle of operation. In actual operation, the injection quan-
2
2-7ON-BOARD DIAGNOSTICS II SYSTEM
1. General

4. Cautions
A: SUPPLEMENTAL RESTRAINT SYSTEM
“AIRBAG”
Airbag system wiring harness is routed near the engine
control module (ECM), main relay and fuel pump relay.
CAUTION:

All Airbag system wiring harness and connectors
are colored yellow. Do not use electrical test equip-
ment on these circuit.

Be careful not to damage Airbag system wiring har-
ness when servicing the engine control module (ECM),
transmission control module (TCM), main relay and
fuel pump relay.
B: PRECAUTIONS
1) Never connect the battery in reverse polarity.

The ECM will be destroyed instantly.

The fuel injector and other part will be damaged in just
a few minutes more.
2) Do not disconnect the battery terminals while the
engine is running.

A large counter electromotive force will be generated in
the alternator, and this voltage may damage electronic
parts such as ECM, etc.
3) Before disconnecting the connectors of each sensor
and the ECM, be sure to turn OFF the ignition switch.
4) Before removing ECM from the located position, dis-
connect two cables on battery.

Otherwise, the ECM may be damaged.
5) The connectors to each sensor in the engine compart-
ment and the harness connectors on the engine side and
body side are all designed to be waterproof. However, it is
still necessary to take care not to allow water to get into the
connectors when washing the vehicle, or when servicing
the vehicle on a rainy day.
H2M1154A
6) Use ECM mounting stud bolts at the body head ground-
ing point when measuring voltage and resistance inside the
passenger compartment.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
4. Cautions