Nissan Frontier D22. Manual — part 832

MTC-50

TROUBLE DIAGNOSIS

PERFORMANCE TEST DIAGNOSES

*1:

MTC-52

*2:

MTC-52

*3:

MTC-53

MHA649A

TROUBLE DIAGNOSIS

MTC-51

C

D

E

F

G

H

I

K

L

M

A

B

MTC

*1:

MTC-42

*2:

MA-15

(KA24DE models) or

MA-24

(VG33E and VG33ER models)

WJIA0282E

MTC-52

TROUBLE DIAGNOSIS

PERFROMANCE CHART
Test Condition

Testing must be performed as follows:

Test Reading

Recirculating-to-Discharge Air Temperature Table

Vehicle location

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

Doors

Closed

Door windows

Open

Hood

Open

TEMP. switch

Max. COLD

Mode switch

(Ventilation) set

REC switch

(Recirculation) set

(blower) speed

4-speed

Engine speed

1,500 rpm

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)

6.6 - 8.3 (44 - 47)

25 (77)

10.4 - 12.4 (51 - 54)

30 (86)

14.2 - 16.7 (58 - 62)

35 (95)

18.2 - 21 (65 - 70)

40 (104)

22.0 - 25.2 (72 - 77)

60 - 70

20 (68)

8.3 - 9.8 (47 - 50)

25 (77)

12.4 - 14.4 (54 - 58)

30 (86)

16.7 - 18.9 (62 - 66)

35 (95)

21.0 - 23.6 (70 - 74)

40 (104)

25.2 - 28.1 (77 - 83)

TROUBLE DIAGNOSIS

MTC-53

C

D

E

F

G

H

I

K

L

M

A

B

MTC

Ambient Air Temperature-to-Operating Pressure Table

TROUBLE DIAGNOSES FOR ABNORMAL PRESSURE

Whenever system's high and/or low side pressure is abnormal, diagnose using a manifold gauge. The marker
above the gauge scale in the following tables indicates the standard (normal) pressure range. Since the stan-
dard (normal) pressure, however, differs from vehicle to vehicle, refer to

MTC-53, "Ambient Air Temperature-

to-Operating Pressure Table"

.

Both High- and Low-Pressure Sides Are Too High.

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 - 1,187 (9.8 - 12.1, 139 - 172)

108 - 157 (1.1 - 1.6, 16 - 23)

25 (77)

1,295 - 1,599 (13.2 - 16.3, 186 - 228)

161.8 - 215.8 (1.65 - 2.2, 23.5 - 31.3)

30 (86)

1,285 - 1,599 (13.1 - 16.0, 186 - 228)

167 - 216 (1.7 - 2.2, 24 - 31)

35 (95)

1,520 - 1,863 (15.5 - 19.0, 220 - 279)

235 - 284 (2.4 - 2.9, 34 - 41)

40 (104)

1,765 - 2,158 (18 - 22, 256 - 313)

289.3 - 353.1 (2.95 - 3.6, 41.9 - 51.2)

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
condenser.

Excessive refrigerant charge
in refrigeration cycle

Reduce refrigerant until speci-
fied pressure is obtained.

Air suction by cooling fan is
insufficient.

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
value quickly drops by
approximately 196 kPa (2

kg/cm

2

, 28 psi). It then

decreases gradually there-
after.

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
little compared with the
specification.

↓

1. Improper thermal valve

installation

2. Improper expansion valve

adjustment

Replace expansion valve.

AC359A