2001 TOYOTA AVALON Service Repair Manual

N13790
Low Pressure
Service Valve
High Pressure
Service Valve
I12287
Properly
Charged
Insufficiently
Charged
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-13
1935 Author
: Date
:
2001 AVALON (RM808U)
3. CHARGE REFRIGERANT INTO REFRIGERANT SYS-
TEM
If there is no leak after refrigerant leak check, charge the proper
amount of refrigerant into refrigeration system.
CAUTION:

Never run the engine when charging the system
through the high pressure side.

Do not open the low pressure hand a valve when the
system is being charged with liquid refrigerant.
(a) Open the high pressure hand valve fully.
(b) Charge specified amount of refrigerant, then close the
high pressure hand valve.
HINT:
A fully charged system is indicated by the sight glass being free
of any bubbles.
(c) Charge partially refrigeration system with refrigerant.
(1) Set vehicle in these conditions:

Running engine at 1,500 rpm

Blower speed control set at ºHIº

Temperature control set at ºMAX. COOLº

Air inlet control set at ºRECIRCº

Fully open doors (Sliding roof: closed)
(2) Open the low pressure hand valve.
CAUTION:
Do not open the high pressure hand valve.
(d) Charge refrigerant until bubbles disappear and check the
pressure on the gauge through the sight glass.
(e) Replenishment to be 100 ± 50 g after bubbles disapper.

AC0YC-02
N13795
Quick Disconnect
Adapter
Charging
Service ValveHose
N13794
Vacuum Pump
Vacuum Pump Adapter
N13791
Low Pressure
Service Valve
Vacuum Pump Adapter High Pressure
Service ValveManifold
Gauge
Set
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-1 1
1933 Author
: Date
:
2001 AVALON (RM808U)
EVACUATING
1. CONNECT QUICK DISCONNECT ADAPTER TO
CHARGING HOSES
2. REMOVE CAPS FROM SERVICE VALVES ON RE-
FRIGERANT LINES
3. SET ON MANIFOLD GAUGE SET
(a) Close both hand valves of manifold gauge set.
(b) Connect the quick disconnect adapters to the service
valves.
4. EVACUATE AIR FROM REFRIGERATION SYSTEM
(a) Connect the vacuum pump adapter to the vacuum pump.
(b) Connect the center hose of the manifold gauge set to the
vacuum pump adapter.
(c) Open both the high and low hand valves and run the vacu-
um pump.
(d) After 10 minutes or more, check that the low pressure
gauge indicates 750 mmHg (30 in. Hg) or more.
HINT:
If the reading is 750 mmHg (30 in. Hg) or more, close both hand
valves of manifold gauge set and stop the vacuum pump.
Check the system for leaks and repair if necessary.
(e) Close both the high and low hand valves and stop the vac-
uum pump.
(f) Leave the system in this condition for 5 minutes or more
and check that there is no gauge indicator.

AC0YE-02
I12953I12946
I12964
Auto A/C:
Ambient Temperature
Sensor
Pressure Switch
Compressor
Relay Block No. 8

No. 2 Cooling Fan Relay

No. 3 Cooling Fan RelayJunction Block No. 8

Heater Main Relay

Magnetic Clutch Relay
Condenser Fan
Condenser
Auto A/C:
Solar Sensor
A/C Control Assembly

Auto A/C:
A/C Amplifier

Manual A/C:
A/C Switch
Manual A/C:
Blower Speed Control Switch

Manual A/C:
Mode Control Switch
Auto A/C:
Room Temperature Sensor
A/C Unit

Heater Radiator

Evaporator

Expansion Valve

Evaporator Temp. Sensor

Auto A/C
Air Mix Servomotor

Air Outlet Servomotor
Blower Unit

Blower Motor

Manual A/C:
Blower Resistor

Auto A/C:
Blower Motor Linear Controller

Air inlet Servomotor
Manual A/C:
Multi Display (Built
into the A/C amplifier)
AC-14
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
1936 Author
: Date
:
2001 AVALON (RM808U)
LOCATION

AC0YB-02
I12286
ight Glass
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-3
1925 Author
: Date
:
2001 AVALON (RM808U)
ON-VEHICLE INSPECTION
1. INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.
Test conditions:
Running engine at 1,500 rpm
Blower speed control switch at ºHIº position
A/C switch ON
Temperature control dial at ºCOOLº position
Fully open the doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer item 3 and 4
3No temperature difference between com-
pressor inlet and outletEmpty or nearly empty
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
4Temperature between compressor inlet and
outlet is noticeably differentCorrect or too muchRefer to items 5 and 6
5Immediately after air conditioning is turned
off, refrigerant in sight glass stays clearToo much
(1) Discharge refrigerant
(2) Evacuate air and charge proper amount
of purified refrigerant
6When air conditioning is turned off, refriger-
ant foams and then stays clearCorrect-
*: Bubbles in the sight glass with ambient temperatures higher than usual can be considered normal if cooling
is sufficient.

I01386
AC-4
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
1926 Author
: Date
:
2001 AVALON (RM808U)
2. INSPECT REFRIGERANT PRESSURE WITH MAN-
IFOLD GAUGE SET
This is a method in which the trouble is located by using a man-
ifold gauge set. Read the manifold gauge pressure when the
these conditions are established.
Test conditions:
Temperature at the air inlet with the switch set
at RECIRC is 30 - 35 °C (86 - 95 °F)
Engine running at 1500 rpm
Blower speed control switch at ºHIº position
Temperature control dial on ºCOOLº position
HINT:
It should be noted that the gauge indications may vary slightly
due to ambient temperature conditions.
(1) Normally functioning refrigeration system.
Gauge reading:
Low pressure side:
0.15 - 0.25 MPa (1.5 - 2.5 kgf/cm
2)
High pressure side:
1.37 - 1.57 MPa (14 - 16 kgf/cm
2)

I01387
Condition : Periodically cools and then fails to cool
I01388
Condition: Insufficient cooling
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-5
1927 Author
: Date
:
2001 AVALON (RM808U)
(2) Moisture present in refrigeration system.
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
During operation, pressure on low
pressure side sometimes become
a vacuum and sometime normal
Moisture entered in refrigeration
system freezes at expansion valve
orifice and temporarily stops cycle,
by normal state is restored after a
time when the ice melts Drier oversaturated state
 Moisture in refrigeration system
freezes at expansion valve orifice
and blocks circulation of refriger-
ant(1) Replace condenser
(2) Remove moisture in cycle
through repeatedly evacuating air
(3) Charge proper amount of new
refrigerant
(3) Insufficient cooling
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low on both low and
high pressure sides
 Bubbles seen in sight glass con-
tinuously
 Insufficient cooling performance
Gas leakage at some place in re-
frigeration systemInsufficient refrigerant in sys-
tem
 Refrigerant leaking
(1) Check for gas leakage with gas
leak detector and repair if neces-
sary
(2) Charge proper amount of re-
frigerant
(3) If indicated pressure value is
near 0 when connected to gauge,
create the vacuum after inspecting
and repairing the location of the
leak

I01389
Condition: Insufficient cooling
I01449
Condition: Does not cool (Cools from time to time in some cases) AC-6
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
1928 Author
: Date
:
2001 AVALON (RM808U)
(4) Poor circulation of refrigerant
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low in both low and
high pressure sides
 Frost on tube from receiver to
unit
Refrigerant flow obstructed by dirt
in receiverReceiver cloggedReplace condenser
(5) Refrigerant does not circulate
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Vacuum indicated on low pres-
sure side, very low pressure indi-
cated on high pressure side
 Frost or dew seen on piping be-
fore and after condenser/ drier or
expansion valve Refrigerant flow obstructed by
moisture or dirt in refrigeration sys-
tem
 Refrigerant flow obstructed by
gas leakage from expansion valve
Refrigerant does not circulate
(1) Check expansion valve
(2) Clean out dirt in expansion
valve by blowing with air
(3) Replace condenser
(4) Evacuate air and charge new
refrigerant to proper amount
(5) For gas leakage from expan-
sion valve, replace expansion
valve

I01390
Condition: Insufficient cooling
I01392
Condition: Insufficient cooling
NOTE : These gauge indica-
tions are shown when the
refrigeration system has
been opened and the refrig-
erant charged without vacu-
um purging.
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-7
1929 Author
: Date
:
2001 AVALON (RM808U)
(6) Refrigerant overcharged or insufficient cooling of
condenser
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 No air bubbles seen through the
sight glass even when the engine
rpm is lowered Unable to develop sufficient per-
formance due to excessive refrig-
eration system
 Insufficient cooling of condenser Excessive refrigerant in
cycle " refrigerant over charged
 Condenser cooling " condenser
fins clogged of condenser fan
faulty
(1) Clean condenser
(2) Check condenser fan motor
operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
(7) Air present in refrigeration system
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 The low pressure piping hot to
touch
 Bubbles seen in sight glass
Air entered in refrigeration system
 Air present in refrigeration sys-
tem
 Insufficient vacuum purging
(1) Check compressor oil to see if
it is dirty or insufficient
(2) Evacuate air and charge new
refrigerant