Trouble Diagnosis For Abnormal Pressure - Suzuki SX4 Service Manual

Thermometer at center ventilation louver
Condition
Crossing point is higher
than acceptable range
("E" area)
Crossing point is lower
than acceptable range
("F" area)

Trouble Diagnosis for Abnormal Pressure

NOTE
Normal pressure values on high side and low side in following table are measured when the ambient
temperature is 30 °C. As normal pressure values on high side and low side vary depending on the
ambient temperature, be sure to perform following steps first when diagnosing troubles.
1. Measure the ambient temperature and using that value, read the normal value from the graph given
in Step 10 of "A/C System Performance Inspection: Manual Type".
2. Put that value in place of the normal pressure in following table.
Manifold gauge MPa (kgf/cm
Lo
0.27 – 0.39 1.13 – 1.56
(2.7 – 3.9) (11.4 – 15.6)
(38.8 – 56.0) (162.3 – 221.8)
Negative pressure 0.5 – 0.6
(5 – 6)
(71.2 – 85.3)
Normal: Normal:
0.27 – 0.39 1.13 – 1.56
(2.7 – 3.9) (11.4 – 15.6)
(38.8 – 56.0) (162.3 – 221.8)
↑ ↓ ↑ ↓
Abnormal: Abnormal:
Negative pressure 0.7 – 1.0
(7 – 10)
(100 – 142)
Possible cause
Insufficient or excessive charge of refrigerant
Dirty or bent A/C evaporator fins
Air leakage from cooling (heater) unit or air duct
Malfunctioning, switch over function of door in
cooling (heater) unit
Compressor malfunction
Insufficient air volume from center duct (Heater
blower malfunction)
Compressor malfunction
Condition
2 ) (psi)
Hi
Normal condition
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.
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.
Air Conditioning System: Manual Type 7B-11
Possible cause
Detail
Dust particles or water
droplets are either
stuck or frozen inside
expansion valve,
preventing the
refrigerant from
flowing.
Expansion valve is
frozen due to moisture
in the system, and
temporarily shuts off
the refrigeration cycle.
Correction
Check refrigerant pressure.
Clean or repair.
Repair or replace.
Repair or replace.
Check compressor.
Check blower motor and fan.
Check compressor.
Correction
—
Replace expansion
valve.
Replace desiccant and
cap with filter.
Evacuate the A/C
system and recharge
with fresh refrigerant.
Replace expansion
valve.
Replace desiccant and
cap with filter.
Evacuate A/C system
and recharge with
fresh refrigerant.
S7RW0A7214002
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