Mitsubishi Montero Sport (2004+). Manual — part 559

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STEP 4. Check that the antenna plug is properly
connected to the radio.

Q: Is the antenna plug properly connected to the

radio?

YES :

Go to Step 7.

NO :

Go to Step 5.

STEP 5. Check that the noise is eliminated when
the antenna plug is properly attached.

Q: Is the noise eliminated?

YES :

Consult the radio manufacturer's service

center.

NO :

Go to Step 6.

STEP 6. Check that the antenna is in good
condition and is properly mounted.

Q: Is the antenna in good condition and is it properly

mounted?

YES :

Consult the radio manufacturer's service

center.

NO :

Go to Step 7.

STEP 7. Clean the antenna plug and ground wire
mounting area. Mount the antenna securely. On a
vehicles with a motor antenna, check the
antenna. (Refer to Inspection Procedure 34 or
35.)
NOTE: Noise encountered during FM reception only
due to differences in FM and AM system, FM is not
as susceptible as AM to interference from engines,
power lines, lighting, etc. On the other hand, due to
the characteristics of FM waves, there are some-

times cases of noise or distortion which are gener-
ated by typical noise interference (first fading and
multipath). (Refer to Inspection Procedure 8.) <Noise
(hissing) occurs in weak signal areas such as moun-
tainous regions, but this is not due to a problem with
the radio.>
NOTE: Furthermore, the amount of interference will
be comparatively less for vehicles equipped with a
diversity antenna system*. If there is an equivalent
amount of distortion in vehicles or radios of the same
type, then differences will be because of differences
in antenna systems, and this should be explained to
the user.
NOTE: Diversity antenna system*: A system where
two types of antenna (glass main antenna and glass
sub antenna) are equipped and the antenna that pro-
vides the best reception car be selected.

Q: Is the antenna in good condition?

YES :

Consult the radio manufacturer's service

center.

NO :

Clean or repair it. Check that the noise is
eliminated. If the noise is not eliminated,
consult the radio manufacturer's service
center.

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INSPECTION PROCEDURE 8: There is More Noise on either AM or FM.

.

DIAGNOSIS
There is much noise only on AM. Due to differences
in AM and FM systems, AM is more susceptible to
noise interference.

STEP 1. Check that there is noise under the
following state(s).

• A motorcycle was passing.

• Lighting was flashing.

• A vehicle passed close by, but it appeared to be a

vehicle generating a particularly large amount of
noise radiation.

• Passed beneath a power line.

• Passed beneath a telephone line.

• Passed close by a signal generator.

• Passed close by some other sources of electrical

noise.

• Passed under a bridge.

Q: Is there noise in the above states?

YES :

Go to Step 3.

NO :

Go to Step 2.

STEP 2. Continue to check for static; when static
is detected, check for the conditions listed
above.

Q: Is there noise in the state described in Step 1?

YES :

Noise prevention on the radio side is

difficult. If the problem is particularly worse
than other radios, consult a service center.

NO :

Go to Step 3.

STEP 3. Check noise prevention on the radio side
is difficult.
NOTE: Noise encountered during FM reception only.
Due to differences in FM and AM systems, FM is not
as susceptible as AM to interference from engines,
power lines, lighting, etc. On the other hand, due to
the characteristics of FM waves, there are some-
times cases of noise or distortion which are gener-
ated by typical noise interference (first fading and
multipath). (Refer to Inspection Procedure 8.) <Noise
(hissing) occurs in weak signal areas such as moun-
tainous regions, but this is not due to a problem with
the radio.> Furthermore, the amount of interference
will be comparatively less for vehicles equipped with
a diversity antenna system. If there is an equivalent
amount of distortion in vehicles or radios of the same
type, then differences will be because of differences
in antenna systems, and this should be explained to
the user.

Q: Is the noise level worse than other radios?

YES :

Consult a service center.

NO :

If the noise level is roughly the same as
other radios, there is no action to be taken.

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INSPECTION PROCEDURE 9: There is Noise when Starting the Engine.

.

DIAGNOSIS

CAUTION

• Connecting a high tension cable to the noise

filter may destroy the noise filter and should
never be done.

• Check that there is no external noise. Since

failure to do this may result in an incorrect
diagnosis due to the inability to identify the
noise source, this operation must be per-
formed.

• Noise prevention should be performed by

suppressing strong sources of noise step by
step.

NOTE: Capacitor: The capacitor does not pass DC
current, but as the number of waves increases when
it passes AC current, impedance (resistance against
AC) decreases, and current flow is facilitated. A
noise suppressing capacitor which take advantage of
this property is inserted between the power line for
the noise source and the ground. This suppresses
noise by grounding the noise component (AC or
pulse signal) to the body of the vehicle.

NOTE: Coil: The coil passes DC current, but imped-
ance rises as the number of waves increases relative
to the AC current. A noise suppressing coil which
takes advantage of this property is inserted into the
power line for the noise source, and works by pre-
venting the noise component from flowing or radiat-
ing out of the line.

NOISE TYPE SOUNDS
ARE IN PARENTHESES

CONDITION

CAUSE

REMEDY

AM, FM: ignition noise
(popping, snapping,
cracking, buzzing)

• Increasing the engine

speed causes the
generator whine
sound to speed up
and the volume to
decrease

• Disappears when the

ignition switch turned
to "ACC" position.

• Mainly due to the

spark plugs

• Due to engine noise

• Check or replace the

ground cable. (Refer
to figure 1, 2, 3 and 4)

• Check or replace the

noise capacitor. (Refer
to figure 5.)

Other electrical
components

-

• Noise may occur as

the electrical
components become
older.

• Repair or replace the

electrical components.

Static electricity (cracking,
crinkling)

• Disappears when the

vehicle is completely
stopped.

• Severe when the

clutch is engaged.

• Occurs when parts or

wiring move for some
reason and contact
metal parts of the
body.

• Return parts or wiring

to their proper
position.

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Static electricity (cracking,
crinkling)

• Various noise are

produced depending
on the body part of the
vehicle.

• Due to removal of the

front hood, bumpers,
exhaust pipe and
muffler, suspension,
etc.

• Ground parts by

bonding.

• Cases where the

problem is not
eliminated by a signal
response to one area
are common, due to
several body parts
being imperfectly
grounded.

NOISE TYPE SOUNDS
ARE IN PARENTHESES

CONDITION

CAUSE

REMEDY

AC002805

(FIGURE 1)

AB

AC002807

(FIGURE 2)

AB

AC002806

(FIGURE 3) <RWD>

AB

AC002808

(FIGURE 4) <4WD>

AB

AC002809

(FIGURE 5)

AB