Owner's Manual

MTC-68
TROUBLE DIAGNOSIS
Revision: March 2005 2005 Altima
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
High-pressure Side is Too Low and Low-pressure Side is Too High
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high and low-pressure
sides are too high.
Pressure is reduced soon after
water is splashed on con-
denser.
Excessive refrigerant charge in
refrigeration cycle
Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.
Insufficient condenser cooling
performance
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cool-
ing fan
● Clean condenser.
● Check and repair cooling fan
as necessary.
● Low-pressure pipe is not
cold.
● When compressor is stopped
high-pressure value quickly
drops by approximately 196
kPa (2 kg/cm
2
, 28 psi). It
then decreases gradually
thereafter.
Poor heat exchange in con-
denser
(After compressor operation
stops, high pressure decreases
too slowly.)
↓
Air in refrigeration cycle
Evacuate repeatedly and
recharge system.
Engine tends to overheat.
Engine cooling systems mal-
function.
Check and repair each engine
cooling system.
● An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.
● Plates are sometimes cov-
ered with frost.
● Excessive liquid refrigerant
on low-pressure side
● Excessive refrigerant dis-
charge flow
● Expansion valve is open a lit-
tle compared with the specifi-
cation.
↓
1. Improper thermal valve
installation
2. Improper expansion valve
adjustment
Replace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.
High-pressure tube or parts
located between compressor
and condenser are clogged or
crushed.
● Check and repair or replace
malfunctioning parts.
● Check lubricant for contami-
nation.
AC360A
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
pickings
Replace compressor.
No temperature difference
between high and low-pres-
sure sides
Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
pickings.
Replace compressor.
AC356A