Suzuki Grand Vitara JB416 / JB420. Manual - part 292

7B-59 Air Conditioning System: 

Reference waveform No. 1
Serial communication line to BCM (1)

A/C System Inspection at ECM

S5JB0A7204051

CAUTION

!

 

• ECM connectors are waterproofed. Each 

terminal of the ECM connectors is sealed 
up with the grommet. Therefore, do not 
measure circuit voltage and resistance by 
inserting the tester’s probe into the sealed 
terminal at the harness side. Or, ECM and 
its circuits may be damaged by water.

• ECM (PCM) cannot be checked by itself.

It is strictly prohibited to connect voltmeter 
or ohmmeter to ECM (PCM) with couplers 
disconnected from it.

 

Voltage Check
ECM (PCM) and its circuits can be checked at ECM 
(PCM) wiring couplers by measuring voltage as follows. 
Refer to “Inspection of ECM and Its Circuits in Section 
1A”.
• C37-12 A/C refrigerant pressure sensor signal
• C37-14 Output of 5 V power source
• C37-15 Ground for ECM
• C37-24 Engine coolant temp. (ECT) sensor signal
• C37-29 Ground for ECM
• C37-30 Ground for ECM
• C37-48 Ground for ECM
• C37-52 CMP sensor signal
• C37-57 Ground for sensors
• C37-58 Ground for ECM
• E23-4 CAN (high) communication line (active high 

signal) to ABS control module

• E23-16 Main power supply
• E23-19 CAN (low) communication line (active low 

signal) to ABS control module

• E23-46 Radiator fan relay No.1 output
• E23-47 Radiator fan relay No.2 output
• E23-48 Radiator fan relay No.3 output
• E23-49 A/C compressor relay output

Measurement terminal

CH1: “G52-11” to “G52-
17”

Oscilloscope setting

CH1: 5 V / DIV
TIME: 20 ms / DIV

Measurement condition

Ignition switch is at ON 
position

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Air Conditioning System:  7B-60

Repair Instructions

Operation Procedure for Charging A/C with Refrigerant

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WARNING

!

 

• Your eyes should not be exposed to refrigerant (liquid). 

Any liquid Refrigerant-134a escaping by accident shows a temperature as low as approx. –6 

°C (21.2 

°F) below freezing point. Should liquid HFC-134a (R-134a) get into your eyes, it may cause a serious 
injury. To protect your eyes against such accident, it is necessary to always wear goggles. Should it 
occur that HFC-134a (R-134a) strikes your eye(s), consult a doctor immediately.
– Do not use your hand to rub the affected eye(s). Instead, use quantities of fresh cold water to 

splash it over the affected area to gradually raise temperature of such area above freezing point.

– Obtain proper treatment as soon as possible from a doctor or eye specialist.

• Should the liquid refrigerant HFC-134a (R-134a) is exposed to your skin, the affected area should be 

treated in the same manner as when skin is frostbitten or frozen.

• Do not handle refrigerant near any place where welding or steam cleaning is performed.
• Refrigerant should be kept in a cold and dark place. It should never be stored in any place where 

temperature is high, e.g. where exposed to direct sun light, close to fire or inside vehicle (including 
trunk room).

• Avoid breathing fume produced when HFC-134a (R-134a) is burned. Such fume may be hazardous to 

your health.

 

Star

Start e

t evacuation.

acuation.

Stop e

Stop evacuation.

acuation.

20 min

20 minutes (abo

utes (above 760 mmHg)

e 760 mmHg)

Wait 10 min

ait 10 minutes

utes

Chec

Check A/C system f

k A/C system for

or

pressure tighteness

pressure tighteness.

Recharge A/C system with

Recharge A/C system with
refr

refriger

igerant.

ant.

Chec

Check A/C system f

k A/C system for refr

or refriger

igerant

ant

leaks and amount of refr

leaks and amount of refriger

igerant

ant

charged.

charged.

Perf

erfor

ormance test

mance test

Inspect and repair connections

Inspect and repair connections.

If gauge sho

If gauge shows

ws

abnor

abnormal conditions

mal conditions

Recharge 570    30 g of

Recharge 570    30 g of
refr

refriger

igerant.

ant.

I5JB0A720031-02

7B-61 Air Conditioning System: 

Recovery
When discharging refrigerant out of A/C system, always 
recover it by using refrigerant recovery and recycling 
equipment (1). Discharging refrigerant HFC-134a 
(R134a) into atmosphere would cause adverse effect to 
environments.

NOTE

• After recovering refrigerant from system 

the amount of removed compressor oil 
must be measured for replenishing 
compressor oil. Refer to “Precautions on 
Replenishing Compressor Oil”.

• When handling recovery and recycling 

equipment, be sure to follow the 
instruction manual for the equipment.

 

Evacuation

CAUTION

!

 

Do not evacuate before recovering 
refrigerant in system.

 

NOTE
Once A/C system circuit is opened (exposed 
to atmospheric air) air conditioning system 
must be evacuated by using a vacuum pump. 
The A/C system should be attached with a 
manifold gauge set, and should be evacuated 
for approx. 20 minutes.

 

1) Connect high charging hose (1) and low charging 

hose (2) of manifold gauge set (3) respectively as 
follows: 
High charging hose (1) 

→ High pressure charging 

valve (4) on discharge hose 
Low charging hose (2) 

→ Low pressure charging 

valve (5) on suction pipe

2) Attach center charging hose (6) of manifold gauge 

set (3) to vacuum pump (7).

3) Operate vacuum pump (7), and then open 

discharge-side valve (9) (Hi) of manifold gauge set 
(3). 
If there is no blockage in the system, there will be an 
indication on high pressure gauge (10). 
In this case, open the other-side valve (8) (Lo) of the 
set and repair the system.

4) Approx. 10 minutes later, low pressure gauge (11) 

should show a vacuum lower than –100 kPa (–1.0 
kg/cm 

2

, –760 mmHg, –14.2 psi) providing no 

leakage exists.

NOTE

• If the system does not show a vacuum 

below –100 kPa (–1.0 kg/cm

2

, –760 mmHg, 

–14.2 psi), close both valves, stop vacuum 
pump and watch movement of low 
pressure gauge.

• Increase in the gauge reading suggests 

existence of leakage. In this case, repair 
the system before continuing its 
evacuation.

• If the gauge shows a stable reading 

(suggesting no leakage), continue 
evacuation.

 

5) Evacuation should be carried out for a total of at 

least 20 minutes.

6) Continue evacuation until low pressure gauge 

indicates a vacuum less than –100 kPa (–1.0 kg/cm

2

, 

–760 mmHg, –14.2 psi), and then close both valves 
(8), (9).

7) Stop vacuum pump (7). Disconnect center charging 

hose (6) from pump inlet. Now, the system is ready 
for charging refrigerant.

1

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8

9

2

1

4

5

11

3

10

6

7

I5JB0A720033-01

Air Conditioning System:  7B-62

Checking of A/C System for Pressure Leaks
After completing the evacuation, close manifold gauge 
high pressure valve (Hi) and low-pressure valve (Lo) and 
wait 10 minutes. Verify that low-pressure gauge reading 
has not changed.

CAUTION

!

 

If the gauge reading moves closer to “0”, 
there is a leak somewhere. Inspect the tubing 
connections, make necessary corrections. 
And then evacuate system once again and 
make sure that there are no leaks.

 

Charge

CAUTION

!

 

• Because the sight glass is not used for this 

A/C system, do not perform an additional 
charge to the A/C system. To charge the 
proper amount of refrigerant, recover and 
evacuate the A/C system first. And then, 
charge the proper amount of refrigerant 
into the A/C system.

• Always charge through low pressure-side 

of A/C system at after the initial charging is 
performed from the high-pressure side 
with the engine stopped.

• Never charge to high pressure-side of A/C 

system with engine running.

• Do not charge while compressor is hot.
• When installing tap valve to refrigerant 

container to make a hole there through, 
carefully follow directions given by 
manufacturer.

• A pressure gauge should always be used 

before and during charging.

• The refrigerant container should be 

emptied of refrigerant when discarding it.

• The refrigerant container should not be 

heated up to 40 

°C (104 °F) or over.

• Refrigerant container should not be 

reversed in direction during charging. 
Reversing in direction causes liquid 
refrigerant to enter compressor, causing 
troubles, such as compression of liquid 
refrigerant and the like.

 

NOTE
The A/C system contains HFC-134a (R-134a).
Described here is a method to charge the A/C 
system with refrigerant from the refrigerant 
service container.
When charging refrigerant recovered by 
using the refrigerant and recycling 
equipment (when recycling refrigerant), 
follow the procedure described in the 
equipment manufacturer’s instruction 
manual.

 

Charge proper amount of refrigerant accurately in 
accordance with the following procedure.

Specified amount of refrigerant
570 

± 30 g (20.1 ± 1.0 oz)

The initial charging of the A/C system is performed from 
the high-pressure side with the engine stopped.
And next, this method must be followed by charging from 
the low-pressure side with the engine running.

1) Check to make sure that hoses are routed properly 

after evacuating the system.

2) Connect low charging hose (1) and high charging 

hose (2) of the manifold gauge set (3) in position. 
Thus open refrigerant container valve (4) to purge 
the charging line.

3) Open the high-pressure side valve (6) and charge 

refrigerant to system.

4) After a while, open the low-pressure side valve (5) 

and close the high-pressure side valve (6).

WARNING

!

 

Make sure that high pressure-side valve is 
closed securely.

 

5

6

1

2

3

4

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