Infiniti M45 (Y34). Manual — part 151

TROUBLE DIAGNOSIS

ATC-89

C

D

E

F

G

H

I

K

L

M

A

B

ATC

PERFORMANCE TEST DIAGNOSIS

*1

ATC-91, "PERFORMANCE
CHART"

.

*2

ATC-91, "PERFORMANCE
CHART"

.

*3

ATC-92, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"

.

*4

ATC-69, "Air Mix Door Motor Circuit"

.

RJIA1601E

ATC-90

TROUBLE DIAGNOSIS

*1

ATC-138, "Removal and Installation
of Compressor Clutch"

.

*2

ATC-75, "Blower Motor Circuit"

.

*3

EM-13, "Checking Drive Belts"

.

RJIA1595E

TROUBLE DIAGNOSIS

ATC-91

C

D

E

F

G

H

I

K

L

M

A

B

ATC

PERFORMANCE CHART
Test Condition

Testing must be performed as follows:

Test Reading

Recirculating-to-discharge Air Temperature Table

Ambient Air Temperature-to-operating Pressure Table

Vehicle location

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

Doors

Closed

Door window

Open

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

25 (77)

8.7 - 10.8 (47.66 - 51.44)

30 (86)

12.5 - 15.3 (54.50 - 59.54)

35 (95)

16.8 - 20.3 (62.24 - 68.54)

60 - 70

25 (77)

10.8 - 12.8 (51.44 - 55.04)

30 (86)

15.3 - 18.0 (59.54 - 64.40)

35 (95)

20.3 - 23.5 (68.54 - 74.30)

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

30 (86)

1,288 - 1,575

(13.13 - 16.06, 187 - 228)

229 - 276 (2.33 - 2.81, 33 - 40)

35 (95)

1,425 - 1,750

(14.53 - 17.84, 207 - 254)

257 - 314 (2.62 - 3.20, 37 - 46)

40 (104)

1,638 - 2,000

(16.70 - 20.39, 237 - 290)

295 - 357 (3.01 - 3.64, 43 - 52)

ATC-92

TROUBLE DIAGNOSIS

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

High-Pressure Side is Too High and Low-Pressure Side is Too Low

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

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

Pressure is reduced soon after
water is splashed on con-
denser.

Excessive refrigerant charge in
refrigeration cycle

Reduce refrigerant until
specified pressure is
obtained.

Air suction by cooling fan is
insufficient.

Insufficient condenser cooling
performance

↓

1. Condenser fins are clogged.

2. Improper fan rotation of cool-

ing fan

●

Clean condenser.

●

Check and repair cooling
fan as necessary.

●

Low-pressure pipe is not
cold.

●

When compressor is stopped
high-pressure value quickly
drops by approximately 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 decreases
too slowly.)

↓

Air in refrigeration cycle

Evacuate repeatedly and
recharge 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.

●

Plates are sometimes cov-
ered with frost.

●

Excessive liquid refrigerant
on low-pressure side

●

Excessive refrigerant dis-
charge flow

●

Expansion valve is open a lit-
tle compared with the specifi-
cation.

↓

●

Improper expansion valve
adjustment

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
located between compressor
and condenser are clogged or
crushed.

●

Check and repair or replace
malfunctioning parts.

●

Check lubricant for contami-
nation.

AC360A