Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 384

7B-27 Air Conditioning System: 

High pressure gauge

[A]: M16 engine model
[B]: J20 engine model

[C]: F9Q engine model

[C]

14.2

28.4

Pressure of Lo

Pressure Gauge

22

312.9

2200

0

1

23

327.1

2300

2

3

30

70

30

70

%

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

21

298.7

2100

20

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

25

30

35

77

86

95

psi

kPa     kg/cm

2

Ambient Temperature

 C
 F

w

Pressure of High Pressure

Gauge

“A”

“B”

“C”

“D

Humidity

Acceptab

le range

Acceptable range

I6JB0A720008-01

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: For 
Petrol Engine Model 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.

Air Conditioning System:  7B-28

Low pressure gauge

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 

15 

°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.

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.

[A]

[B]

T

e

mp

. at Air Outlet of Center 

V

entilation Louv

er 

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

46.4

48.2

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

82.4

25

30

35

77

86

95

 F       C

 C
 F

“E”

“F”

Temp. near Air Inlet of HVAC unit

30

70

%

Humidity

Acceptable range

T

emp

. at Air Outlet of Center 

V

entilation Louv

er 

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

46.4

48.2

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

82.4

25

30

35

77

86

95

 F       C

 C
 F

“E”

“F”

Temp. near Air Inlet of HVAC unit

30

70

%

Humidity

Acceptable range

I5JB0A720013-03

7B-29 Air Conditioning System: 

Thermometer at center duct

NOTE
If ambient temperature is within 30 

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

to the following table.

 

[A]: M16 engine model
[B]: J20 engine model

[C]: F9Q engine model

T

e

mp

. at Air Outlet of Center 

V

e

ntilation Louv

er 

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

[C]

46.4

48.2

7

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

25

30

35

77

86

95

 F       C

 C
 F

“E”

“F”

Temp. near Air Inlet of HVAC unit

30

70

%

Humidit

y

Acceptable range

I6JB0A720009-01

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-30

Condition

Possible Cause

Correction

Manifold Gauge

MPa

(kg/cm

2

)

(psi)

Detail

Lo

Hi

M16 engine model

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

J20 engine model

0.22 – 0.31

(2.2 – 3.1)

(31 – 44)

F9Q engine model

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

M16 engine model

0.96 – 1.16
(9.6 – 11.6)

(136 – 165)

J20 engine model

1.10 – 1.45

(11.0 – 14.5)

(156 – 206)

F9Q engine model

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:

M16 engine model

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

J20 engine model

0.22 – 0.31

(2.2 – 3.1)

(31 – 44)

F9Q engine model

0.23 – 0.33

(2.3 – 3.3)

(33 – 47)

↑ ↓

Abnormal:

Negative pressure

Normal:

M16 engine model

0.96 – 1.16
(9.6 – 11.6)

(136 – 165)

J20 engine model

1.10 – 1.45

(11.0 – 14.5)

(156 – 206)

F9Q engine model

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.