MTC-106
TROUBLE DIAGNOSIS
Revision: January 2005 2004 Quest
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.
High- and low-pressure sides
become equal soon after com-
pressor operation stops.
Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
No temperature difference
between high- and low-pres-
sure sides.
Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
● There is a big temperature
difference between receiver
drier outlet and inlet. Outlet
temperature is extremely
low.
● Liquid tank inlet and expan-
sion valve are frosted.
Liquid tank inside is slightly
clogged.
● Replace liquid tank.
● Check lubricant for contami-
nation.
● Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
● Expansion valve inlet may
be frosted.
● Temperature difference
occurs somewhere in high-
pressure side.
High-pressure pipe located
between receiver drier and
expansion valve is clogged.
● Check and repair malfunc-
tioning parts.
● Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or only cool
when touched.
Low refrigerant charge.
↓
Leaking fittings or compo-
nents.
Check refrigerant system for
leaks. Refer to MTC-159,
"Checking for Refrigerant
Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.
Expansion valve closes a little
compared with the specifica-
tion.
↓
1. Improper expansion valve
adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be
clogged.
● Remove foreign particles by
using compressed air.
● Check lubricant for contami-
nation.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.
Low-pressure pipe is clogged
or crushed.
● Check and repair malfunc-
tioning parts.
● Check lubricant for contami-
nation.
Air flow volume is too low. Evaporator is frozen.
● Check intake sensor circuit.
Refer to MTC-113, "
Intake
Sensor Circuit" .
● Replace compressor.
AC353A
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