Mitsubishi MOTORS Laser 1991, Service Manual, Page: 302 / 320

Troubleshooting
Trouble symptom
Engine would not start.
[Engine starting is possible
when the starter relay is in the
switched-off (normally closed)
condition, with the clutch
switch is the switch-off and
the ECU harness connector
disconnected.]
Cause
C h e c k m e t h o d Remedy.
There is a short-circuit of Check by using check Repair the harness.
the starter relay activation chart
circuit
Engine would not start.
[When the ECU harness
connector is disconnected, the
theft-alarm starter relay is
switched-off (normally closed)
and the engine starts (inhibitor
switch at or
There is a short-circuit of
the theft-alarm starter
relay activation circuit
Check by using check
chart Repair the harness.
When, as a test of the alarm,
a door or the
is opened
without using the key, or the
hood is opened from within
the vehicle, the theft-alarm
horn sounds but the headlights
don’t flash.
(The headlights can, however,
be switched ON by using the
passing switch.)
Damaged or disconnected Check by using check
Repair the harness or
wiring of diode chart
replace the diode
Replace the headlight
Damaged or disconnected
relay or the headlight.
wiring of headlight power Replace the daytime
supply circuit or headlight running light relay.
activation circuit
Malfunction of the ECU Replace the ECU.
The headlights flash during an
alarm test but the horn does
not sound.
The system is not deactivated
when, during an alarm test in
which the alarm is intentionally
activated, the door or
is
unlocked by using the key.
(The system also cannot be
disarmed.)
Damaged or disconnected Check by using check
Repair the harness.
wiring of horn relay
chart
Replace the horn.
power supply circuit or Replace the sub fusible
horn activation circuit link.
Malfunction of the ECU Replace the ECU.
Damaged or disconnected If input checks Repair the harness.
wiring of door key indicate a malfunction, Replace the key
cylinder and check by using check cylinder switch or the
unlock switch input circuit chart switch.
Malfunction of door key
cylinder and
unlock switch.
ECU: Electronic Control Unit
Malfunction of the ECU Replace the ECU.
NOTE
If the 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 alarm
canceling 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
the shorting is
If the is opened
using
a key and is left as opened when the door key cylinder switch system has
a trouble (wiring harness damage, open circuit, etc.), the ECU judges it as the holding mode and
does not produce alarm even when the door is opened,