1992 MITSUBISHI 3000GT alarm

Downloaded from www.Manualslib.com manuals search engine iCHASSIS ELECTRICAL
- Theft-alarm Svstem54-221
(Output)Voltmeter rvv 1-1
Scan tool(Buzzer %,isound)16FO5712. Make sure that when the following switches are turned
on, the output shown in the illustration is delivered. (Only
those switches which are related to the theft-alarm system
are listed here.)
0Driver and front passenger door switchesl Headlight switch
lDriver and front passenger door lock switchesl Passing light switch
l Pop-up switch (up to 1993 models)
l Hood switch
l
Liftgate switch
l Door key cylinder switch
l
Liftgate switch
If there is no output of a voltage pattern at all, check
for a malfunction of that switch or for damaged or discon-
nected wiring.
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Downloaded from www.Manualslib.com manuals search engine 54-222CHASSIS ELECTRICAL - Theft-alarm System
TROUBLESHOOTING QUICK-REFERENCE TABLE
For information concerning the locations of electrical components, refer to GENERAL-Theft-alarm System
Circuit.
1.ARMING / DISARMING RELATIONSHIP
Trouble symptomThe system is not armed (The
SECURITY light doesn’t illumi-
nate, and the alarm doesn’t func-
tion.)
(The central door locking system
functions normally.
If the central locking system doesnot function normally, refer to
GROUP 42.)
The arming procedures are fol-
lowed, but the SECURITY light
does not illuminate.(There is an alarm, however,
when an alarm test is conductedafter about 20 seconds have
passed.)
The alarm sounds in error when,
while the system is armed, a door
or the liftgate is unlocked by us-
ing the key.
ICause
Damaged or disconnected
wiring of ECU power sup-
ply circuit
Damaged or disconnected
wiring of door switch input
circuit
Damaged or disconnectedwiring of SECURITY light
activation circuit.Blown SECURITY light
bulb
Malfunction of the ECU.
Damaged or disconnected
wiring of a door key cylin-
der and the
liftgate unlock
switch input circuit.
Malfunction of a door key
cylinder and the liftgate un-
lock switch.
Malfunction of the ECU.
2.ACTIVATION / DEACTIVATION RELATIONSHIP
Trouble symptomCauseThere is no alarm when, as an
Damaged or disconnected
alarm test, a door is opened with-wiring of door switch (all
out using the key.doors) input circuit
(The arming and disarming arenormal, and the alarm is
acti-Malfunction of the door
vated when the liftgate or hood isswitch
opened.)
Malfunction of the ECUThere is no alarm when, as an
Damaged or disconnected
alarm test, the liftgate is opened
without using the key.wiring of liftgate switch in-
put circuit
(The alarm is activated, however,
by opening a door or the hood.)Malfunction of the liftgate
switch.
Malfunction of the ECU.Check methodCheck by using check
chart P.54-224.Check by using check
chart P.54-225.Check by using check
chart P.54-229.
If input checks
(P.54-220) indicate amalfunction, check by
using check chart
P&f-227.
Check method
If input checks
(P.54-220) indicate a
malfunction, check by
using check chart
P.54-225.
If input checks
(P.54-220) indicate a
malfunction, check by
using check chart
P.54-228.
Remedy
Replace the fusible link
No. (6) or the fuse No.
(19).Repair the harness.
Repair the harness or re-
place the door switch.
Replace the fusible linkNo. (6) or the fuse No.(1%
Repair the harness.
Replace the bulb.
Replace the ECU.
Repair the harness or re-
place a door key cylinderand the
liftgate unlock
switch.
Replace the ECU.
Remedy
Repairthe harness or re-
place the door switch.
Replace the ECU.
Repair the harness or re-
place the liftgate switch.
Replace the ECU.
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Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Theft-alarm System54-223
Trouble symptom
Cause
Check method
Remedy
There is no alarm when, as analarm test, the hood is openedDamaged or disconnected
wiring of hood switch input
If input checks
Repairthe harness or re-
from within the vehicle.circuit.
(P.54-220) indicate aplace the hood switch.
(The alarm is activated, however,malfunction, check by
I
by opening a door or the liftgate.)using check chartMalfunction of the hood p.54-225.
switch.
Malfunction of the ECU.
-Replace the ECU.
Engine would not start [EngineThere is a short-circuit of
starting is possible when the the starter relay activationCheck by using check
chart P.54-234.
Repair the harness.
starter relay is in the switched-off
circuit
(normally closed) condition, with
the clutch switch in the switch-off
and the ECU harness connector
disconnected.]
When, as a test of the alarm, aDamaged or disconnectedCheck by using check
door or the
liftgate is opened wiring of headlight power chart P.54-231, 232.
Repairthe harness or re-
without using the key, orthe hood
is opened from within the vehicle,supply circuit or headlightplace the diode Ds.
activation circuitReplace the headlight
the horn and the theft-alarm hornrelay or the headlight.sound but the headlights don’t
flash. (The headlights can, how-
ever, be switched. ON by usingMa
lfunction of the ECUReplace the ECU.
the passing switch.)The headlights flash during an
alarm test but the horn orthe theftDamaged or disconnectedCheck by using checkRepair the harness.
alarm horn does not sound.wiring of horn relay power
chart P.54-229,230,231.supply circuit or horn ac-Replace the horn.
tivation circuitReplace dedicated fuse
Damaged or disconnectedNo. (6) or the fusible linkwiring of the theft-alarmNo. (6).horn relay power supply
circuit or the theft-alarm
horn activation circuit.
Malfunction of the ECU.
Replace the ECU.The system is not deactivated
nhen, during an alarm test in
Damaged or disconnected
If input checks
which the alarm is intentionallywiring of door key cylinder
Repair the harness.activated, the door or
liftgate isand
liftgate unlock switch(P.54-220) indicate a
input circuitmalfunction, check byReplace the key cylinder
Jnlocked by using the key.
using check chartswitch or the
liftgate
switch.
:The system also cannot be dis-P.54-227,228.
armed.)
Malfunction of door keycyl-inder and liftgate unlock
switch.
Malfunction of the ECU
Replace the ECU.
ECU: Electronic Control Unit
NOTEIf the
lifigate unlock switch or door key cylinder unlock switch is operated roughly, or if these switches have
been installed incorrectly or switches themselves are defective the ECU may not accept the warning or alarmcancelling signal. In such case, the alarm operation will take place when the door is opened using a key.
[When the door key cylinder switch has been shorted, however, if the ignition switch is turned ON, the ECU
judges the detection-switch as faulty and thereafter, it will prevent setting of (warning) alarm until the shorting
is corrected.]
If the
liftgate is opened using a key and is left opened when the door key cylinder switch system has a trouble
(wiring harness damage, open circuit, etc.), the ECU judges it as the
liftgate holding mode and does not producealarm even when the door is opened.
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CHECKING THE CIRCUIT AND INDIVIDUAL PART1. ETACS POWER-SUPPLY AND GROUND CIRCUITS
Description of operationThe battery supplies a stabilized 5 V power supply to the
ECU, via the constant-voltage circuit and terminal 51 (which
is directly connected to the battery).
ECU terminal voltage (Connection condition of the ECU con-
nector).
I
ECU
SignalConditionTerminal
terminal No.
voltage
51ECU power supplyAt all times12v
2. KEY-REMINDER SWITCH INPUT CIRCUIT
Description of operationThe key-reminder switch is switched OFF and HIGH-level
signals are sent to the ECU when the key is inserted into
the ignition key cylinder: when the key is removed, the key-re-
minder switch is switched ON and LOW-level signals are sentto the ECU.
ECU terminal voltage (Connection condition of the ECU con-
nector).
I
ECUTerminal
terminal No.SignalConditionvoltage
\
L)
L)
64Key-reminder
switch
Key removed12 V
Key inserted0 V
d
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LCHASSIS ELECTRICAL
- Theft-alarm System54-225NOTE
rl:UP to 1993 moaelsf2:From 1994 modet.sKX55-AK-R540¶-N3. HOOD SWITCH INPUT CIRCUIT
Description of operation
When the hood is closed (the hood switch is switched OFF),
HIGH-level signals are sent to the ECU:
When the hood is opened (the hood switch is switched ON),
LOW-level signals are sent to the ECU.
ECU terminal voltage (Connection condition of the. ECU con-
nector).
ECU
terminal
No.
18
Signal
conditionTerminal
voltage
Hood switch HoodOpen OV
Closed 5
V*
*Measurement is not possible by using a voltmeter, but is possible
by using an oscilloscope.4. DOOR SWITCH INPUT CIRCUIT
Description of operation
When the door is closed (the door switch is switched OFF),
HIGH-level signals are sent to the ECU:
When the door is opened (the door switch is switched ON),
LOW-level signals are sent to the ECU.
ECU terminal voltage (Connection condition of the ECU).
ECU
terminal
No.Signal
ConditionTerminal
voltage
10Driver door Driver
switchdoorOpen OV
Closed 5 V*
Passenger
Passen-Open 0 V
door switchger door Closed5 v*I,I
II*Measurement is not possible by using a voltmeter, but is possible
by using an oscilloscope.
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Downloaded from www.Manualslib.com manuals search engine 54-226CHASSIS ELECTRICAL - Theft-alarm System
5. DOOR LOCK ACTUATOR SWITCH INPUT CIRCUIT
Description of operation
When a door is locked by the lock knob or the key, the door
lock actuator switch is switched OFF, and HIGH-level signals
are sent to the ECU. These signals activate the timer circuit
of the R ECU, thereby causing the activation circuit to function,thus
R activating the door lock actuator of all doors.
ECU terminal voltage (Connection condition of the ECU con-
nector).
ECU
terminal
No.
13
14
!
I
t
((
Signal
Door lock ac-
tuator switch
(driver door)
loor lock ac-
uator
switch
:passenger
joor)ConditionTerminal
voltage
Door
Lock:5 V’lock ac- OFF
tuator
switchUnlock: ON 0 V
DoorLock:‘5 v*lock ac- OFF
tuator
switchUnlock: ON 0 V
*Measurement is not possible by using a voltmeter, but is possible
by using an oscilloscope.
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Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Theft-alarm System54-227
:Up to 1993 models>

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KXSS-NC-R5‘05-N6. DOOR KEY CYLINDER UNLOCK AND
LIFTGATE
CYLINDER LOCK SWITCH INPUT CIRCUIT
Description of operation
When the door key is rotated or the liftgate key is unlocked,
R LOW-level signals are sent to the ECU.ECU terminal voltage (Connection condition of the ECU
R
connector).

ECU
terminal No.
19
Signal
Door key cyl-
inder unlock
switch
20Liftgate un-
lock switch
19
20
Door key cyl-
inder unlock
switch
Liftgate un-
lock switch
L
ConditionTerminal
voltage
Door
Not
5Vkey cyl- rotate
inder
0-WRotate 0 V
Door
Not5vkey cyl- rotate
inder
(Wrotateov
LiftgateLock 5 V
Unlock 0 V
Condition
Terminal
voltage
Door
Not
5vkey cyl- rotate
inder
0-WRotate 0 V
Door
Not5vkey cyl- rotate
inder
W-0Rotate 0 V
LiftgateLock 5 V
Unlock 0 V
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Downloaded from www.Manualslib.com manuals search engine 54-228CHASSIS ELECTRICAL - Theft-alarm Svstem
7.
LIFTGATE SWITCH INPUT CIRCUIT
Description of operationWhen the
liftgate is closed (the liftgate switch is switched
ROFF), HIGH-level signals are sent to the ECU. When the
liftgate is opened (the liftgate switch is switched R ON), LOW-level signals are sent to the ECU.
ECU terminal voltage (Connection condition of the ECU con-
nector).
ECU
terminal No.Signal
I
ConditionTerminal
voltage
17Liftgate
switch
_l
Measurement is not possible by using a voltmeter, but is possible
by using an oscilloscope.
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