Infiniti QX56 (Z62). Manual — part 771

PERFORMANCE TEST

HA-25

< BASIC INSPECTION >

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PERFORMANCE TEST

Inspection

INFOID:0000000006276158

INSPECTION PROCEDURE

1.

Connect recovery/recycling/recharging equipment (for HFC-134a) or manifold gauge.

2.

Start the engine, and set to the following condition.

Test condition

3.

Maintain test condition until A/C system becomes stable. (Approximately 10 minutes)

4.

Check that test results of “recirculating-to-discharge air temperature” and “ambient air temperature-to-
operating pressure” are within the specified value.

5.

When test results are within the specified value, inspection is complete.
If any of test result is out of the specified value, perform diagnosis by gauge pressure. Refer to

HA-27,

"Symptom Table"

.

RECIRCULATING-TO-DISCHARGE AIR TEMPERATURE TABLE

FRONT

REAR

Surrounding condition

Indoors or in the shade (in a well-ventilated place)

Vehicle condition

Door

Closed

Door glass

Full open

Hood

Open

Engine speed

Idle speed

A/C condition (front/rear)

Temperature control switch or dial

Full cold

A/C switch

ON

Air outlet

VENT (ventilation)

Intake door position

Recirculation

Fan speed

Maximum speed set

Inside air (Recirculating air) at blower assembly inlet

Discharge air temperature from center ventilator

°

C (

°

F)

Relative humidity

%

Air temperature

°

C (

°

F)

50 – 60

20 (68)

6.8 - 8.8 (44 - 48)

25 (77)

10.4 - 12.9 (51 - 55)

30 (86)

13.9 - 16.9 (57 - 63)

35 (95)

17.3 - 20.8 (63 - 70)

60 – 70

20 (68)

8.8 - 10.8 (48 - 52)

25 (77)

12.9 - 15.4 (55 - 60)

30 (86)

16.9 - 19.9 (63 - 68)

35 (95)

20.8 - 24.3 (70 - 76)

Inside air (Recirculating air) at blower assembly inlet

Discharge air temperature from rear ventilator grille A RH*

°

C (

°

F)

Relative humidity

%

Air temperature

°

C (

°

F)

50 – 60

20 (68)

11.4 - 13.4 (53 - 56)

25 (77)

15.8 - 18.3 (60 - 65)

30 (86)

20.9 - 23.9 (70 - 75)

35 (95)

25.9 - 29.4 (79 - 85)

HA-26

< BASIC INSPECTION >

PERFORMANCE TEST

*: Measuring point of temperature is 5 mm (1.99 in) from air outlet end of rear ventilator grille A RH (passenger
room side).

AMBIENT AIR TEMPERATURE-TO-OPERATING PRESSURE TABLE

60 – 70

20 (68)

13.4 - 15.4 (56 - 60)

25 (77)

18.3 - 20.8 (65 - 69)

30 (86)

23.9 - 26.9 (75 - 80)

35 (95)

29.4 - 32.9 (85 - 91)

Inside air (Recirculating air) at blower assembly inlet

Discharge air temperature from rear ventilator grille A RH*

°

C (

°

F)

Relative humidity

%

Air temperature

°

C (

°

F)

Fresh air

High-pressure (Discharge side)

kPa (bar, kg/cm

2

, psi)

Low-pressure (Suction side)

kPa (bar, kg/cm

2

, psi)

Relative humidity

%

Air temperature

°

C (

°

F)

50 – 70

25 (77)

1,106 - 1,351

(11.06 - 13.51, 11.28 - 13.79,

160.3 - 196)

243 - 297

(2.43 - 2.97, 2.48 - 3.03, 35.3 -

43.1)

30 (86)

1,306 - 1,596

(13.06 - 15.96, 13.32 - 16.28,

189.4 - 231.5)

280 - 342

(2.80 - 3.42, 2.86 - 3.49, 40.6 -

49.6)

35 (95)

1,555 - 1,900

(15.55 - 19.00, 15.86 - 19.38,

225.4 - 275.5)

323 - 394

(3.23 - 3.94, 3.29 - 4.02, 46.8 -

57.2)

40 (104)

1,734 - 2,119

(17.34 - 21.19, 17.68 - 21.61,

251.4 - 307.2)

348 - 425

(3.49 - 4.25, 3.55 - 4.33, 50.4 -

61.6)

REFRIGERATION SYSTEM SYMPTOMS

HA-27

< SYMPTOM DIAGNOSIS >

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SYMPTOM DIAGNOSIS

REFRIGERATION SYSTEM SYMPTOMS

Trouble Diagnosis For Unusual Pressure

INFOID:0000000006276159

Diagnose using a manifold gauge whenever system’s high and/or low side pressure(s) is/are unusual. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Refer to
above table (Ambient air temperature-to-operating pressure table) since the standard (usual) pressure, how-
ever, differs from vehicle to vehicle.

Symptom Table

INFOID:0000000006276160

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

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

The pressure returns to nor-
mal soon after sprinkling wa-
ter on condenser.

Overfilled refrigerant.

Collect all refrigerant, evacuate
refrigerant cycle again, and
then refill it with the specified
amount of refrigerant.

Air flow to condenser is insuf-
ficient.

Insufficient condenser cooling
performance.
• Poor fan rotation of radiator

and condenser.

• Improper installation of air

guide.

• Clogged or dirty condenser

fins.

• Repair or replace malfunc-

tioning parts.

• Clean and repair condenser

fins.

When compressor is stopped,
a high-pressure reading
quickly drops by approximate-

ly 196 kPa (2 kg/cm

2

, 28 psi).

It then gradually decreases.

Air mixed in refrigerant cycle.

Collect all refrigerant, evacuate
refrigerant cycle again, and
then refill it with the specified
amount of refrigerant.

• Low-pressure pipe is cooler

than the outlet of evapora-
tor.

• Low-pressure pipe is frost-

ed.

Expansion valve opened too
much (excessive flow of refrig-
erant).

Replace expansion valve.

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

High-pressure pipe and upper
side of condenser become
hot, however, liquid tank does
not become so hot.

Clogged or crushed high-pres-
sure pipe located between
compressor and condenser.

Repair or replace the malfunc-
tioning parts.

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

• The readings of both sides

become equal soon after
compressor operation
stops.

• There is no temperature dif-

ference between high- and
low-pressure sides.

Malfunction in compressor sys-
tem (insufficient compressor
pressure operation).
• Damage or breakage of

valve.

• Malfunctioning gaskets.

Replace compressor.

AC359A

AC360A

AC356A

HA-28

< SYMPTOM DIAGNOSIS >

REFRIGERATION SYSTEM SYMPTOMS

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

• The area around evapora-

tor outlet does not become
cold.

• The area around evapora-

tor inlet becomes frosted.

Clogged expansion valve.
• Breakage of temperature

sensor.

• Clogging by foreign material.

Eliminate foreign material from
expansion valve, or replace it.

• There is a temperature dif-

ference between the areas
around outlet and inlet
pipes of liquid tank.

• Liquid tank becomes frost-

ed.

Malfunction in inner liquid tank
(clogged strainer).

Replace liquid tank.

Evaporator becomes frosted.

Clogged or crushed low-pres-
sure pipe.

Repair or replace malfunction-
ing parts.

Malfunction in intake sensor .

Check intake sensor system.
Refer to

HAC-80, "Diagnosis

Procedure"

.

There is a small temperature
difference between the high
and low pressure pipes for re-
frigerant cycle.

• Shortage of refrigerant.
• Leakage of refrigerant.

• Check for leakage.
• Collect all refrigerant, evacu-

ate refrigerant cycle again,
and then refill it with the spec-
ified amount of refrigerant.

Low-pressure side sometimes be-
comes negative.

• Sometimes the area

around evaporator outlet
does not become cold.

• Sometimes the area

around evaporator inlet is
frosted.

• Icing caused by the mixing of

water in cooler cycle.

• Deteriorated dryer in liquid

tank.

• Collect all refrigerant.
• Evacuate refrigerant cycle

completely, and then refill it
with the specified amount of
refrigerant. At this time, al-
ways replace liquid tank.

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

AC353A

AC354A