A/C System Performance Inspection: Notes

Confirm that vehicle and environmental conditions are as follows.
- Vehicle is not exposed to direct sun.
- Ambient temperature is within 15 - 35 °C (59 - 95°F).
Make sure that high pressure valve (1) and low pressure valve (2) of manifold gauge set (3) are firmly closed.
Connect high pressure charging hose (4) to high pressure service valve (5), and connect low pressure charging hose (6) to low pressure service valve (7).
Bleed the air in charging hoses (4), (6) by loosening their respective nuts on manifold gauge set (3), utilizing the refrigerant pressure. When a hissing sound is heard, immediately tighten nut.

Fig 1: Bleeding Air In Charging Hoses
Courtesy of SUZUKI OF AMERICA CORP.
Warm up engine to normal operating temperature (engine coolant temperature at 80 - 90 °C (176 - 194°F)) and keep it at specified idle speed. (Radiator cooling fan should not be working when checking temperature.)
Set A/C switch to ON position, blower speed selector at "H" (4th position), temperature selector at "COOL", air flow selector at "FACE" and air intake selector at "RECIRCULATION". (Confirm that A/C compressor and condenser cooling fan are working.)
Keep all windows, doors and engine food open.

Performance diagnosis condition

Ambient temperature: 15-35°C (59 - 95°F)

Engine RPM: Keep to 1,500 RPM.

Blower speed selector: "H" (4th position)

Temperature selector: "Cool"

Air flow selector: "Face"

Vehicle doors: All open

Air intake selector: Recirculation
With dry bulb thermometer (1) inserted into center ventilation louver and another one set near recirculation air inlet, read temperature indicated on each thermometer.

Fig 2: Inserting Into Center Ventilation Louver
Courtesy of SUZUKI OF AMERICA CORP.
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.
NOTE: Pressure registered on gauge varies with ambient temperature. Therefore, use the graphs when determining if pressures are normal or not.

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: 1400-1750 kPa (14.0 - 17.5 kg/cm ² , 199.1 - 248.9 psi)

Pressure on low pressure gauge: 230 - 350 kPa (2.3 - 3.5 kg/cm ² , 32.7 - 49.8 psi)

Fig 3: Identifying Ambient Temperature Graph
Courtesy of SUZUKI OF AMERICA CORP.