Infiniti M45 (Y34). Manual - part 151

 

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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

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

 

 

 

 

 

 

 

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