Infiniti G35 (V35) Sedan. Manual — part 744

HA-10

< FUNCTION DIAGNOSIS >

VARIABLE DISPLACEMENT COMPRESSOR SYSTEM

and also the piston stroke decrease. In other words, crankcase pressure increase triggers pressure differ-
ence between the piston and the crankcase. The pressure difference changes the angle of the swash plate.

SJIA0548E

REFRIGERATION SYSTEM SYMPTOMS

HA-11

< SYMPTOM DIAGNOSIS >

C

D

E

F

G

H

J

K

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M

A

B

HA

N

O

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SYMPTOM DIAGNOSIS

REFRIGERATION SYSTEM SYMPTOMS

SYMPTOM DIAGNOSIS PROCEDURE

SYMPTOM DIAGNOSIS PROCEDURE : Trouble Diagnosis For Unusual Pressure

INFOID:0000000000959841

Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-to-operating pressure table).

BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO HIGH

BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO HIGH : Symptom Table

INFOID:0000000000959842

HIGH-PRESSURE SIDE IS TOO HIGH AND LOW-PRESSURE SIDE IS TOO LOW

HIGH-PRESSURE SIDE IS TOO HIGH AND LOW-PRESSURE SIDE IS TOO LOW :
Symptom Table

INFOID:0000000000959843

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Both high- and low-pressure sides
are too high.

The pressure returns to nor-
mal is reduced soon after wa-
ter is splashed on condenser.

Excessive refrigerant charge in
refrigeration cycle.

Reduce refrigerant until speci-
fied pressure is obtained.

Air suction by cooling fan is in-
sufficient.

Insufficient condenser cooling
performance.

↓

1.

Condenser fins are
clogged.

2.

Improper fan rotation of
cooling fan.

• Clean condenser.
• Check and repair cooling fan

as necessary.

• Low-pressure pipe is not

cold.

• When compressor is

stopped high-pressure val-
ue quickly drops by approx-

imately 196 kPa (2 kg/cm

2

,

28 psi). It then decreases
gradually thereafter.

Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreas-
es too slowly.).

↓

Air in refrigeration cycle.

Evacuate repeatedly and re-
charge system.

Engine tends to overheat.

Engine cooling systems mal-
function.

Check and repair each engine
cooling system.

• An area of the low-pressure

pipe is colder than areas
near the evaporator outlet.

• Low-pressure pipe is some-

times covered with frost.

• Excessive liquid refrigerant

on low-pressure side.

• Excessive refrigerant dis-

charge flow.

• Expansion valve is open a lit-

tle compared with the speci-
fication.

↓

Improper expansion valve ad-
justment.

Replace expansion valve.

AC359A

HA-12

< SYMPTOM DIAGNOSIS >

REFRIGERATION SYSTEM SYMPTOMS

HIGH-PRESSURE SIDE IS TOO LOW AND LOW-PRESSURE SIDE IS TOO HIGH

HIGH-PRESSURE SIDE IS TOO LOW AND LOW-PRESSURE SIDE IS TOO HIGH :
Symptom Table

INFOID:0000000000959844

BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO LOW

BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO LOW : Symptom Table

INFOID:0000000000959845

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

High-pressure side is too high and
low-pressure side is too low.

Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.

High-pressure tube or parts lo-
cated between compressor
and condenser are clogged or
crushed.

• Check and repair or replace

malfunctioning parts.

• Check lubricant for contami-

nation.

AC360A

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

High-pressure side is too low and
low-pressure side is too high.

High- and low-pressure sides
become equal soon after com-
pressor operation stops.

Compressor pressure opera-
tion is improper.

↓

Damaged inside compressor
packings.

Replace compressor.

No temperature difference be-
tween high- and low-pressure
sides.

Compressor pressure opera-
tion is improper.

↓

Damaged inside compressor
packings.

Replace compressor.

AC356A

REFRIGERATION SYSTEM SYMPTOMS

HA-13

< SYMPTOM DIAGNOSIS >

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LOW-PRESSURE SIDE SOMETIMES BECOMES NEGATIVE

LOW-PRESSURE SIDE SOMETIMES BECOMES NEGATIVE : Symptom Table

INFOID:0000000000959846

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Both high- and low-pressure sides
are too low.

• There is a big temperature

difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.

• Liquid tank inlet and expan-

sion valve are frosted.

Liquid tank inside is slightly
clogged.

• Replace liquid tank.
• Check lubricant for contami-

nation.

• Temperature of expansion

valve inlet is extremely low
as compared with areas
near liquid tank.

• Expansion valve inlet is

frosted.

• Temperature difference oc-

curs somewhere in high-
pressure side.

High-pressure pipe located be-
tween liquid tank and expan-
sion valve is clogged.

• Check and repair malfunc-

tioning parts.

• Check lubricant for contami-

nation.

Expansion valve and liquid
tank are warm or slightly cool
when touched.

Low refrigerant charge.

↓

Leaking fittings or compo-
nents.

Check refrigerant for leaks.
Refer to

HA-34, "Refrigerant

Leaks"

.

There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.

Expansion valve closes a little
compared with the specifica-
tion.

↓

1.

Improper expansion
valve adjustment.

2.

Malfunctioning expansion
valve.

3.

Outlet and inlet may be
clogged.

• Remove foreign particles by

using compressed air.

• Replace expansion valve.
• Check lubricant for contami-

nation.

An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.

Low-pressure pipe is clogged
or crushed.

• Check and repair malfunc-

tioning parts.

• Check lubricant for contami-

nation.

Air flow volume is not enough
or is too low.

Evaporator is frozen.

• Check intake sensor circuit.

Refer to

HAC-102, "Diagno-

sis Procedure"

.

• Replace compressor.
• Repair evaporator fins.
• Replace evaporator.
• Refer to

HAC-86, "WITH

LEFT AND RIGHT VENTI-
LATION TEMPERATURE
SEPARATELY CONTROL
SYSTEM : Diagnosis Proce-
dure"

.

AC353A