Mitsubishi Outlander (2013+). Manual — part 745

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONER AND VENTILATION

55-36

REFRIGERANT GAS PRESSURE CHECK

CAUTION

• The temperature of equipment in the engine

room is high and the refrigerant gas pressure
is also high immediately after the engine and
A/C operation are stopped, thus leave the
vehicle for a while, and then perform the
refrigerant gas pressure check.

• On completion, stop the engine and wait until

the high-pressure side of the gauge manifold
is depressurised. Then remove the quick
joints and the others.

CAUTION

•

AC106028

A

AB

Sleeve

ACB03699

High-pressure
side service valve

Low-pressure
side service valve

AB

Place the quick joint onto the service valve, and

press to fit the part A securely until the sleeve
clicks into place.

•

AC106029

Low-pressure
valve

Gauge manifold

Charging hose (red)

Quick joint
(for high-
pressure)

Quick joint
(for low-
pressure)

AB

Charging hose (blue)

High-
pressure valve

When connecting, run your hand along the
hose while pressing to ensure that there are
no bends in the hose.

1. Check that the engine and A/C are stopped.

2. Close the high-pressure valve of the gauge

manifold.

3. Connect the charging hose (red) to the

hi-pressure side of the gauge manifold.

4. Connect the quick joint (for high pressure) to the

charging hose (red).

5. Install the quick joint (for high pressure) to the

high-pressure side service valve of the vehicle.

6. Close the low-pressure valve of the gauge

manifold.

7. Connect the charging hose (blue) to the

low-pressure side of the gauge manifold.

8. Connect the quick joint (for low pressure) to the

charging hose (blue).

9. Install the quick joint (for low pressure) to the

low-pressure side service valve of the vehicle.

10.Start and fully warm up the engine, and then

check that the engine speed of the test condition
is satisfied.

11.Set the A/C control panel to the mode instructed

in the test conditions.

12.Measure the high pressure/low pressure, and

check that the measurement is within the
permissible range of the table below. If the value
is outside the permissible range, refer to the
cooling performance check result, and perform a
check according to the diagnosis chart of
refrigerant system.

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONER AND VENTILATION

55-37

NOTE: Prior to the measurement, wait until the
refrigerant pressure is stable. (Approximately 10
minutes after A/C operation start)

Garage ambient temperature
°C

20

25

30

35

40

45

50

Compressor high pressure kPa 881

−

1, 377

1, 086

−

1, 582

1,291

−

1,787

1,496

−

1,992

1,701

−

2,197

1,906

−

2,402

2,111

−

2,607

Compressor low pressure kPa

204

−

369

255

−

420

306

−

471

357

−

522

408

−

573

459

−

624

510

−

675

DIAGNOSIS BY REFRIGERANT
PRESSURE

M1552023000225

A/C
system
symptom

Measurement circumstance

Cause

Measures

Hig
h
pres
sure

Low
pres
sure

Air
outl
et
tem
pera
ture

Note

Cooler is
not
effective.

Low High High

• Pressure for low

pressure side is high,
and high pressure
side is low.

• When the A/C

operation is stopped,
the pressures of low
pressure side and
high pressure side
immediately become
identical.

• Leakage inside

compressor

• Faulty

compression of
compressor

1. Check according to the

compressor check.
1. When no foreign object

is present to the oil, and
when the colour is light
grey, replace only the
compressor.

2. When foreign objects

are mixed to the oil, and
the colour is black,
replace the compressor
and receiver.

2. Perform the evacuation

sufficiently to remove the
foreign objects and
moisture in the cycle.

3. Fill the new gas to the

specified amount.

High High High

• Low pressure

side/high pressure
side pressure is too
high.

• Low pressure side

piping is too hot to
touch.

• Air is mixed to

the refrigerant
cycle.

• Evacuation is

insufficient.

1. Perform the evacuation

sufficiently, and remove
the foreign objects and
moisture in the cycle.

2. Fill the new gas to the

specified amount.

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONER AND VENTILATION

55-38

Sufficient
cooling and
insufficient
cooling
occur
periodically.

Fluc
tuati
on

Fluc
tuati
on

Fluc
tuati
on

During the air
conditioner operation,
the low pressure side
pressure alternates
between the negative
pressure and normal.
(also in the high
pressure side, the
abnormal and normal
statuses are alternated).

The moisture in
the refrigerant
cycle becomes
frozen in the
expansion valve,
then the
circulation of
refrigerant is
stopped
temporarily.
Subsequently, the
status recovers to
normal by the
melting of ice.

1. Replace the receiver

(drier).

2. Perform the evacuation

sufficiently, and remove
the moisture in the cycle.

3. Fill the new refrigerant to

the specified amount.

Cooler is
sometimes
not
effective.
(works
occasionall
y)

Low Vac

uum

Fluc
tuati
on

• The low pressure

side pressure
indicates the
vacuum, and the high
pressure side
indicates the low
pressure.

• To the piping before

and after the
expansion valve,
frost or dew is
observed.

• The foreign

objects or
moisture inside
the refrigerant
cycle deposits
or
freezes inside
the expansion
valve, and the
refrigerant flow
is disturbed.

• Because of the

expansion
valve operation
failure, the
refrigerant flow
is disturbed.

1. Check the expansion

valve.
1. If foreign objects are

present inside the
expansion valve,
remove them by using
an air gun or others.

2. When no foreign object

is present, the
expansion valve
operation failure is
suspected. Therefore,
replace the expansion
valve.

2. Perform the evacuation

sufficiently, and remove
the foreign objects and
moisture in the cycle.

3. Fill the new refrigerant to

the specified amount.

A/C
system
symptom

Measurement circumstance

Cause

Measures

Hig
h
pres
sure

Low
pres
sure

Air
outl
et
tem
pera
ture

Note

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONER AND VENTILATION

55-39

Cooling
effectivene
ss is bad.

Low Low Slig

htly
high

• Low pressure

side/high pressure
side pressure is low.

• Outlet air

temperature is high.

• Gas leakage is

present to
somewhere in
the refrigerant
cycle.

• Refrigerant gas

amount is
insufficient.

1. When the pressure gauge

indication is close to zero,
check the leak position,
and then repair the
leakage. Also, when the
value is lower than the
standard pressure, check if
the gas leakage is present,
and repair if necessary.

2. After checking the leak

position, sufficiently
perform the evacuation,
then fill the new gas to the
specified amount.

High High Slig

htly
high

Low pressure side/high
pressure side pressure
is too high.

• Refrigerant

amount is
excessive.

• Condenser

cooling is
insufficient.

1. Clean the condenser fin

(fouling, fin clogging)

2. Check the condenser fan

motor (radiator fan)
operation.

3. When 1 and 2 are normal,

recover all the refrigerant.
Then, perform a sufficient
evacuation again, and fill
the new gas to the
specified amount.

High High High

• Low pressure

side/high pressure
side pressure is too
high.

• Frost or dew is

formed to the low
pressure side.

Expansion valve
trouble (valve
opened
excessively)

Replace the expansion valve.

Nor
mal

Nor
mal

Slig
htly
high

-

Because of the
slight difference of
measurement
environment,
secular change of
vehicle, or others,
it is possible that
the outlet
temperature
fluctuation has
occurred.

Check the status for a while,
and if the status does not
improve, recover all the
refrigerant, then fill to the
appropriate amount.

A/C
system
symptom

Measurement circumstance

Cause

Measures

Hig
h
pres
sure

Low
pres
sure

Air
outl
et
tem
pera
ture

Note