DIAGNOSTICS [K200] 4-7
2. Performance Test Diagnosis
2. Performance Test Diagnosis
If various conditions caused to other air conditioning system, the characteristics revealed on manifold gauge
reading are shown in the following:
As to the method of a performance test, refer to the item of  Performance Test .
Each shaded area on the following tables indicates a reading of the normal system when the temperature
of outside air is 32.5°C (91°F).
Condition Probable cause Corrective action
INSUFFICIENT REFRIGERANT CHARGE Insufficient cooling Refrigerant is small, or (1) Perform leak test.
leaking a little. (2) Repair leak.
(3) Charge system.
Evacuate, as
necessary, and
recharge system.
G4M0673
ALMOST NO REFRIGERANT No cooling action Serious refrigerant leak. Stop compressor
immediately.
(1) Perform leak test.
(2) Discharge system.
(3) Repair leak(s).
(4) Replace receiver
drier if necessary.
(5) Check oil level.
(6) Evacuate and
recharge system.
G4M0674
FAULTY EXPANSION VALVE Slight cooling; Expansion valve If valve inlet reveals
Sweating or frosted restricts refrigerant flow. sweat or frost:
expansion valve inlet. I Expansion valve is (1) Discharge system
clogged. (2) Remove valve and
I Expansion valve is clean it. Replace it if
inoperative. necessary.
I Valve stuck closed. (3) Evacuate system
I Thermal bulb has lost (4) Charge system.
charge. If valve does not oper-
ate:
(1) Discharge system.
(2) Replace valve.
(3) Evacuate and
G4M0675
charge system.
35
4-7 [K200] DIAGNOSTICS
2. Performance Test Diagnosis
Condition Probable cause Corrective action
Insufficient cooling; Expansion valve allows Check valve for opera-
Sweated suction line. too much refrigerant tion. If suction side does
No cooling; through evaporator. not show a pressure
Sweating or frosted suc- Faulty seal of O-ring in decrease, replace valve.
tion line. expansion valve. (1) Discharge system.
(2) Remove expansion
valve and replace
O-ring.
(3) Evacuate and
replace system.
G4M0676
G4M0677
AIR IN SYSTEM Insufficient cooling Air mixed with refriger- (1) Discharge system.
ant in system. (2) Replace receiver
drier.
(3) Evacuate and
charge system.
G4M0678
MOISTURE IN SYSTEM After operation for a Drier is saturated with (1) Discharge system.
while, pressure on suc- moisture. Moisture has (2) Replace receiver
tion side may show frozen at expansion drier (twice if neces-
vacuum pressure read- valve. Refrigerant flow sary).
ing. During this is restricted. (3) Evacuate system
condition, discharge air completely (repeat
will be warm. As warn- 30-minute evacuating
ing of this, reading three times.).
shows 39 kPa (0.4 (4) Recharge system.
kg/cm2, 6 psi) vibration.
G4M0679
36
DIAGNOSTICS [K200] 4-7
2. Performance Test Diagnosis
Condition Probable cause Corrective action
FAULTY CONDENSER No cooling action; Condenser is often I Check condenser
Engine may overheat. found not functioning cooling fan.
Suction line is very hot. well. I Check condenser for
dirt accumulation.
I Check engine cooling
system for overheat.
I Check for refrigerant
overcharge.
If pressure remains
high in spite of all
above actions taken,
remove and inspect
the condenser for
G4M0680
possible oil clogging.
HIGH-PRESSURE LINE BLOCKED Insufficient cooling; Drier is clogged, or (1) Discharge system.
Frosted high-pressure restriction in high- pres- (2) Remove receiver
liquid line. sure line. drier or strainer and
replace it.
(3) Evacuate and
charge system.
G4M0681
FAULTY COMPRESSOR Insufficient cooling Internal problem is in (1) Discharge system.
compressor, or dam- (2) Remove and check
aged gasket and valve. compressor.
(3) Repair or replace
compressor.
(4) Check oil level.
(5) Replace receiver
drier.
(6) Evacuate and
charge system.
G4M0682
37