Mitsubishi Montero Sport (2004+). Manual — part 601

ON-VEHICLE SERVICE

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-31

COMPRESSOR NOISE CHECK

M1552008700216

.

You must first know the conditions when the noise occurs.
These conditions are: weather, vehicle speed, in gear or neu-
tral, engine temperature or any other special conditions. Noises
that develop during A/C operation can often be misleading. For
example: what sounds like a failed front bearing or connecting
rod, may be caused by loose bolts, nuts, mounting brackets, or
a loose clutch assembly. Verify accessory drive belt tension
(power steering or generator). Improper accessory drive belt
tension can cause a misleading noise when the compressor is
engaged and little or no noise when the compressor is disen-
gaged. Drive belts are speed-sensitive. That is, at different
engine speeds, and depending upon belt tension, belts can
develop unusual noises that are often mistaken for mechanical
problems within the compressor.

.

ADJUSTMENT
1. Select a quiet area for testing. Duplicate conditions as much

as possible. Switch compressor on and off several times to
clearly identify compressor noise. To duplicate high ambient
conditions (high head pressure), restrict air flow through
condenser. Install manifold gauge set to make sure
discharge pressure doesn't exceed 2,070 kPa (300 psi).

2. Tighten all compressor mounting bolts, clutch mounting bolt,

and compressor drive belt. Check to assure clutch coil is
tight (no rotation or wobble).

3. Check refrigerant hoses for rubbing or interference that can

cause unusual noises.

4. Check refrigerant charge. (Refer to

P.55-28

.)

5. Recheck compressor noise as in Step 1.
6. If noise still exists, loosen compressor mounting bolts and re

torque. Repeat Step 1.

7. If noise continues, replace compressor and repeat Step 1.

ON-VEHICLE SERVICE

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-32

POWER RELAY CHECK

M1552008800376

BLOWER RELAY

A/C COMPRESSOR RELAY, CONDENSER FAN
MOTOR RELAY

BATTERY
CONNECTION

TESTER
CONNECTION

SPECIFIED
CONDITION

Not applied

4

− 5

Open circuit

• Connect

terminal 3 to the
positive battery
terminal

• Connect

terminal 1 to the
negative battery
terminal

4

− 5

Less than 2 ohms

AC002841AB

BLOWER

RELAY

BATTERY
CONNECTION

TESTER
CONNECTION

SPECIFIED
CONDITION

Not applied

1

− 3

Open circuit

• Connect

terminal 2 to the
positive battery
terminal

• Connect

terminal 4 to the
negative battery
terminal

1

− 3

Less than 2 ohms

AC002843AC

CONDENSER FAN

MOTOR RELAY

A/C

COMPRESSOR

CLUTCH RELAY

ON-VEHICLE SERVICE

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-33

REAR HEATER RELAY

BATTERY
CONNECTION

TESTER
CONNECTION

SPECIFIED
CONDITION

Not applied

1

− 3

Open circuit

• Connect terminal 2 to

the positive battery
terminal

• Connect terminal 4 to

the negative battery
terminal

1

− 3

Less than 2
ohms

AC002844 AB

REAR HEATER RELAY

ON-VEHICLE SERVICE

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-34

IDLE-UP OPERATION CHECK

M1552001600241

.

1. Before inspection and adjustment, set vehicle in the

following condition:

• Engine coolant temperature: 80 − 90 °C (176 − 194 °F)

• Lights, electric cooling fan and accessories: Set to OFF

• Transmission: " N " or " P " position

• Steering wheel: Straightforward

2. Check whether or not the idling speed is the standard value.

Standard value: 700

± 100 r/min

NOTE: There is no necessity to make an adjustment,
because the idling speed is automatically adjusted by the
idle speed control system. If, however, there occurs a devia-
tion from the standard value for some reason, check the idle
speed control system. Refer to GROUP 13A, On-vehicle
Service

P.13A-883

.

3. When the A/C is running after turning the A/C switch to ON,

and the blower switch to the MH or HI position, check to be
sure that the idle speed is at the standard value.

Standard value:

NOTE: It depends on the outside air temperature signal
whether a low load, a middle load or a high load is applied to
the air conditioning. The PCM receives the signal via the
automatic compressor controller and determines whether
the air conditioning is working under high, middle or low
load.

VEHICLE CONDITION

IDLE-UP
SPEED r/min

When the air conditioning is working
under low load (Outside air temperature
sensor: ON)

750

± 100

When the air conditioning is working
under high load (Outside air temperature
sensor: OFF)

900

± 100