Infiniti FX35 / FX45. Manual - part 120

ATC-76

< SERVICE INFORMATION >

TROUBLE DIAGNOSIS

PERFORMANCE TEST DIAGNOSIS

*10

ATC-50, "Operational Check"

*11

ATC-4, "Precaution for Working with 
HFC-134a (R-134a)"

*12

EM-14, "Checking Drive Belts"

 

(VQ35DE) or 

EM-170, "Checking 

Drive Belts"

 (VK45DE)

*13

EC-437, "Description"

 (VQ35DE) or 

EC-1030, "Description"

 (VK45DE)

*1

"PERFORMANCE CHART"

*2

"PERFORMANCE CHART"

*3

"TROUBLE DIAGNOSIS FOR UN-
USUAL PRESSURE"

*4

ATC-59, "Air Mix Door Motor Circuit"

SJIA1226E

TROUBLE DIAGNOSIS

ATC-77

< SERVICE INFORMATION >

C

D

E

F

G

H

I

K

L

M

A

B

ATC

N

O

P

PERFORMANCE CHART

Test Condition

Testing must be performed as follows:

*1

ATC-125, "Removal and Installation 
of Compressor Clutch"

*2

ATC-64, "Blower Motor Circuit"

*3

EM-14, "Checking Drive Belts"

 

(VQ35DE) or 

EM-170, "Checking 

Drive Belts"

 (VK45DE)

SJIA1642E

Vehicle condition

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

Doors

Closed

Door windows

Open

ATC-78

< SERVICE INFORMATION >

TROUBLE DIAGNOSIS

Test Reading

Recirculating-to-discharge Air Temperature Table

Ambient Air Temperature-to-operating Pressure Table

TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE

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

Hood

Open

TEMP.

Max. COLD

Mode switch

 (Ventilation) set

Intake switch

 (Recirculation) set

 Fan (blower) speed

Max. speed set

Engine speed

Idle speed

Operate the air conditioning system for 10 minutes before taking measurements.

Inside air (Recirculating air) at blower assembly inlet

Discharge air temperature at center ventilator

°

C (

°

F)

Relative humidity

%

Air temperature

°

C (

°

F)

50 - 60

20 (68)

11.2 - 13.2 (52 - 56)

25 (77)

12.2 - 14.8 (54 - 59)

30 (86)

15.5 - 18.6 (60 - 65)

35 (95)

21.0 - 24.5 (70 - 76)

40 (104)

28.7 - 32.6 (84 - 91)

60 - 70

20 (68)

13.2 - 15.2 (56 - 59)

25 (77)

14.8 - 17.3 (59 - 63)

30 (86)

18.6 - 21.6 (65 - 71)

35 (95)

24.5 - 28.0 (76 - 82)

40 (104)

32.6 - 36.5 (91 - 98)

Ambient air

High-pressure (Discharge side)

kPa (kg/cm

2

, psi)

Low-pressure (Suction side)

kPa (kg/cm

2

, psi)

Relative humidity

%

Air temperature

°

C (

°

F)

50 - 70

20 (68)

961 - 1,167

(9.8 - 11.9, 139 - 169)

216 - 265

(2.2 - 2.7, 31 - 38)

25 (77)

1,108 - 1,353

(11.3 - 13.8, 161 - 196)

230 - 281

(2.3 - 2.9, 33 - 41)

30 (86)

1,275 - 1,549

(13.0 - 15.8, 185 - 225)

261 - 320

(2.7 - 3.3, 38 - 46)

35 (95)

1,549 - 1,893

(15.8 - 19.3, 225 - 274)

297 - 364

(3.0 - 3.7, 43 - 53)

40 (104)

1,814 - 2,216

(18.5 - 22.6, 263 - 321)

357 - 435

(3.6 - 4.4, 52 - 63)

Vehicle condition

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

TROUBLE DIAGNOSIS

ATC-79

< SERVICE INFORMATION >

C

D

E

F

G

H

I

K

L

M

A

B

ATC

N

O

P

High-pressure Side is Too High and Low-pressure Side is Too Low

High-pressure Side is Too Low and Low-pressure Side is Too High

Both High- and Low-pressure Sides are Too Low

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 water 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

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