Suzuki Grand Vitara JB419. Manual - part 126

Air Conditioning System: 7B-10

10) Check for each pressure of low side and high side if

it is within shaded range of graph. If each gauge
reading is out of specified pressure, correct defective
part referring to the table.

Low side and high side pressure example,
gauges should read as follows when ambient
temperature is 30

°C (86 °F)

Pressure on high pressure gauge (HI): 1570 –
1970 kPa (15.7 – 19.7 kg/cm

, 223 – 280 psi)

Pressure on high pressure gauge (LO): 230 – 330
kPa (2.3 – 3.3 kg/cm

, 33 – 47 psi)

NOTE
Pressure registered on gauge varies with
ambient temperature. Therefore, use the
graphs when determining if pressures are
normal or not.

High pressure gauge

Low pressure gauge

14.2

28.4

Pressure of Lo

Pressure Gauge

312.9

2200

327.1

2300

298.7

2100

42.7

56.9

71.1

85.3

99.5

113.8

128.0

142.2

151.4

170.6

184.9

199.1

213.3

227.5

241.7

256.0

270.2

284.4

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

psi

kPa kg/cm

Ambient Temperature

C
F

Pressure of High Pressure

Gauge

“A”

“B”

“C”

“D”

Humidity

Acceptab

le range

Acceptable range

I5JB0B720006-03

Condition

Possible Cause

Correction

Pressure is higher than
acceptable range
(“A” area)

Refrigerant overcharged

Recharge.

Expansion valve frozen or clogged

Check expansion valve.

Clogged refrigerant passage of high side

Clean or replace.

Radiator cooling fan malfunction (Insufficient
cooling of condenser)

Check radiator cooling fan.

Dirty or bent condenser fins (Insufficient
cooling of condenser)

Clean or repair.

Compressor malfunction (Insufficient oil etc.) Check compressor.
Engine overheat

Check engine cooling system referring to
“Engine Cooling Symptom Diagnosis in
Section 1F”.

Pressure is lower than
acceptable range
(“B” area)

Insufficient refrigerant (Insufficient charge or
leakage)

Check for leakage, repair if necessary and
recharge.

Expansion valve malfunction (valve opens too
wide)

Check expansion valve.

Compressor malfunction (Insufficient
compression)

Check compressor.

Condition

Possible Cause

Correction

Pressure is higher than
acceptable range
(“C” area)

Expansion valve malfunction (valve opens too
wide)

Check expansion valve.

Compressor malfunction (Insufficient
compression)

Check compressor.

Pressure is lower than
acceptable range
(“D” area)

Insufficient refrigerant (Insufficient charge or
leakage)

Check for leakage, repair if necessary and
recharge.

Expansion valve malfunction (valve opens too
narrow)

Check expansion valve.

Clogged refrigerant passage (crashed pipe)

Repair or replace.

7B-11 Air Conditioning System:

11) Check inlet port temperature-to-outlet port temperature relationship using graph.

For example, if A/C evaporator inlet port temperature is 30

°C (86 °F) and center ventilation louver temperature is

°C (59 °F), their crossing point is within acceptable range as shown in the graph in this case, cooling

performance is satisfactory and proper.

12) If crossing point is out of acceptable range, diagnose trouble referring to the following table.

Thermometer at center duct

NOTE
If ambient temperature is approximate 30

°C (86 °F), it is possible to diagnose A/C system in detail

referring to the following table.

. at Air Outlet of Center

ntilation Louv

46.4

48.2

44.6

50.0

51.8

53.6

55.4

57.2

59.0

60.8

62.6

64.4

66.2

68.0

69.8

71.6

73.4

75.2

77.0

78.8

80.6

F C

C
F

“E”

“F”

Temp. near Air Inlet of HVAC unit

Humidity

Acceptable range

I5JB0B720007-02

Condition

Possible Cause

Correction

Crossing point is higher
than acceptable range
(“E” area)

Insufficient or excessive charge of refrigerant Check refrigerant pressure.
Dirty or bent A/C evaporator fins

Clean or repair.

Air leakage from cooling (heater) unit or air
duct

Repair or replace.

Malfunctioning, switch over function of
damper in cooling (heater) unit

Repair or replace.

Compressor malfunction

Check compressor.

Crossing point is lower
than acceptable range
(“F” area)

Insufficient air volume from center duct
(Heater blower malfunction)

Check blower motor and fan.

Compressor malfunction

Check compressor.

Air Conditioning System: 7B-12

Condition

Possible Cause

Correction

Manifold Gauge

MPa

(kg/cm

)

(psi)

Detail

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

1.57 – 1.97

(15.7 – 19.7)

(223 – 280)

Normal condition

—

Negative pressure

0.5 – 0.6

(5 – 6)

(71.2 – 85.3)

The low pressure side
reads a negative pressure,
and the high pressure side
reads an extremely low
pressure.
Presence of frost around
tubing to and from receiver/
dryer and expansion valve.

Dust particles or water
droplets are either stuck
or frozen inside
expansion valve,
preventing the
refrigerant from flowing.

Clean expansion valve.
Replace it if it cannot be
cleaned.
Replace desiccant.
Evacuate the A/C
system and recharge
with fresh refrigerant.

Normal:

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

↑ ↓

Abnormal:

Negative pressure

Normal:

1.57– 1.97

(15.7 – 19.7)

(223 – 280)

↑ ↓

Abnormal:

0.7 – 1.0

(7 – 10)

(100 – 142)

During A/C operation, the
low pressure side
sometimes indicates
negative pressure, and
sometimes normal
pressure. Also high
pressure side reading
fluctuates between the
abnormal and normal
pressure.

Expansion valve is
frozen due to moisture
in the system, and
temporarily shuts off the
refrigeration cycle.

Replace expansion
valve.
Replace desiccant.
Evacuate A/C system
and recharge with fresh
refrigerant.

0.05 – 0.15

(0.5 – 1.5)

(4.2 – 21.3)

0.7 – 1.0

(7 – 10)

(100 – 142)

Both low and high pressure
sides indicate low readings.
Output air is slightly cold.

Insufficient refrigerant in
system. (Refrigerant
leaking)

Using a gas leak
detector, check for leaks
and repair as necessary.
Recharge refrigerant to a
specified amount.
If the pressure reading is
almost 0 when the
manifold gauges are
attached, check for any
leaks, repair them, and
evacuate the system.

0.4 – 0.6

(4 – 6)

(56.9 – 85.3)

Pressure on low pressure
side is high.
Pressure on high pressure
side is low.
Both pressure becoming
equal right after A/C is
turned OFF.

Internal leak in
compressor

Inspect compressor and
repair or replace as
necessary.

7B-13 Air Conditioning System:

0.35 – 0.45

(3.5 – 4.5)

(50 – 64)

2.0 – 2.5

(20 – 25)

(285 – 355)

High pressure reading on
both low and high pressure
sides.

Overcharged A/C
system.
Faulty condenser
cooling operation.
Faulty radiator fan
operation.

Adjust refrigerant to
specified amount.
Clean condenser.
Inspect and repair
radiator fan.

High pressure reading on
both low and high pressure
sides.
Low pressure side tubing is
not cold when touched.

Presence of air in A/C
system. (Improperly
evacuated)

Replace desiccant.
Inspect quantity of
compressor oil and
presence of
contaminants in oil.
Evacuate system and
recharge with fresh
refrigerant.

0.45 – 0.55

(4.5 – 5.5)

(64 – 78)

High pressure reading on
both low and high pressure
sides.
Large amount of frost or
dew on the low pressure
side tubing.

Faulty expansion valve.
Refrigerant flow is not
regulated properly.

Replace expansion
valve.

Condition

Possible Cause

Correction

Manifold Gauge

MPa

(kg/cm

)

(psi)

Detail

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