Toyota Avalon (XX50): Refrigerant

On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

HINT:

The following examples show the readings of a manifold gauge set and the corresponding air conditioning system problems.

(a) Read the manifold gauge pressure when the following conditions are met:

• The doors are fully open.
• The engine is idling (for Gasoline Model) or power switch is on (READY) (for HV Model).
• The A/C switch is on.
• The temperature is set to max cold.
• The blower speed is set to high.
• The temperature at the air inlet with recirculate selected is 30 to 35°C (86 to 95°F).

(1) Normal functioning air conditioning system Gauge Reading Pressure Side Refrigerant Volume Low 150 to 250 kPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi) High 1370 to 1570 kPa (14.0 to 16.0 kgf/cm2, 199 to 228 psi)

*a LO *b HI

(2) Abnormally functioning air conditioning system

1. During operation, pressure on low pressure side cycles between normal and vacuum

   Symptom	Air conditioning system periodically cools and then fails to cool
   Probable Cause	Moisture in air conditioning system freezes at expansion valve orifice, causing refrigerant to temporarily stop circulating
   	After system stops and warms up again, ice melts and normal operation is temporarily restored
   Diagnosis	Cooler dryer (integrated into condenser tank) saturated with moisture
   	Moisture in air conditioning system is freezing at expansion valve orifice and blocking circulation of refrigerant
   Corrective Actions	Replace cooler dryer
   	Remove moisture by repeatedly evacuating air from air conditioning system
   	Recharge air conditioning system with proper amount of new or purified refrigerant

   HINT:

   For the example above, moisture is present in the air conditioning system.

2. Pressure is low on both low and high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively
   	Insufficient cooling performance
   Probable Cause	Refrigerant leaks from air conditioning system
   Diagnosis	Insufficient refrigerant
   	Refrigerant leaking
   Corrective Actions	Check for refrigerant leaks and repair if necessary
   	Recharge air conditioning system with proper amount of new or purified refrigerant
   	If gauges indicate pressure of close to 0, then it is necessary to evacuate air conditioning system after repairing leaks

   HINT:

   For the example above, there is insufficient refrigerant.

3. Pressure is low on both low and high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively
   	Frost exists on pipe from condenser to evaporator unit
   Probable Cause	Refrigerant flow is obstructed by dirt inside pipes of condenser core
   Diagnosis	Condenser is clogged
   Corrective Actions	Replace condenser

   HINT:

   For the example above, there is poor circulation of refrigerant.

4. Vacuum is indicated on low pressure side and very low pressure is indicated on high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively (System may cool occasionally)
   	Frost or condensation is seen on piping on both sides of receiver/dryer or expansion valve
   Probable Cause	Refrigerant flow is obstructed by moisture or dirt in air conditioning system
   	Expansion valve is stuck closed
   Diagnosis	Refrigerant does not circulate
   Corrective Actions	Replace expansion valve
   	Replace condenser
   	Evacuate air conditioning system and recharge with proper amount of new or purified refrigerant

   HINT:

   For the example above, the refrigerant does not circulate.

5. Pressure is too high on both low and high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively
   Probable Cause	Unable to provide sufficient performance due to excessive amount of refrigerant
   	Cooling effectiveness of condenser is insufficient
   Diagnosis	Excessive amount of refrigerant in air conditioning system because excessive refrigerant was added during recharging
   	Cooling effectiveness of condenser is insufficient because condenser fins are clogged or cooling fan is faulty
   Corrective Actions	Clean condenser
   	Check operation of condenser cooling fan
   	If condenser is clean and fan operation is normal, check amount of refrigerant and recharge air conditioning system with proper amount of new or purified refrigerant

   HINT:

   For the example above, the air conditioning system is overcharged or cooling effectiveness of condenser is insufficient.

6. Pressure is too high on both low and high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool
   	The low pressure piping is too hot to touch
   Probable Cause	Air in air conditioning system
   Diagnosis	Air present in air conditioning system
   	Insufficient vacuum purging when evacuating air conditioning system
   Corrective Actions	Replace cooler dryer
   	Check compressor oil to see if it is dirty or insufficient
   	Evacuate air conditioning system and recharge it with new or purified refrigerant

   NOTICE:

   These gauge indications occur when the air conditioning system has been left open and then recharged without evacuating the system.

   HINT:

   For the example above, air is present in the air conditioning system.

7. Pressure is too high on both low and high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively
   	Frost or large amount of condensation on piping on low pressure side
   Probable Cause	Expansion valve may be stuck open or metering refrigerant incorrectly
   Diagnosis	Excessive refrigerant in low pressure piping
   	Expansion valve open too wide
   Corrective Actions	Replace expansion valve

   HINT:

   For the example above, there is an expansion valve malfunction.

8. Pressure is too high on both low and high pressure side or pressure is too low on high pressure side

   *a	LO
   *b	HI

   Symptom	Air conditioning system does not cool effectively
   Probable Cause	Internal leak in compressor
   Diagnosis	Low compression
   	Leak from damaged valve or other compressor component
   Corrective Actions	Replace compressor

   HINT:

   For the example above, there is insufficient compressor compression.

(3) Gauge readings (Reference)

Precaution

PRECAUTION

PRECAUTIONS FOR REFRIGERANT HFO-1234yf (R1234yf)

(a) Compatibility

(1) The parts used in the refrigerant cycle, the compressor oil, etc. of an HFO-1234yf (R1234yf) system are not compatible with a conventional HFC-134a (R134a) system.

(b) HFO-1234yf (R1234yf) Refrigerant

(1) Always use HFO-1234yf (R1234yf) as the refrigerant.

NOTICE:

• Do not charge the system with refrigerant near open flame, as HFO-1234yf (R1234yf) is combustible.

• When charging the system with refrigerant, make sure that the area is well ventilated (especially be careful in areas where the gas can easily accumulate, such as under lifts and in garage pits, as the gas is heavier than air).

• Follow any local regulations regarding combustible gases.

• Be sure to use a refrigerant recovery unit that is compatible with HFO-1234yf (R1234yf) systems.

HINT:

The shape of the service port for refrigerant charging has an exclusive design conforming to international standards for HFO-1234yf (R1234yf) to prevent improper refrigerant charging.

(c) Compressor Oil (for Gasoline Model)

(1) Always use ND-OIL 12 as the compressor oil.

NOTICE:

The oil used for HFC-134a (R134a) systems (ND-OIL 8) does not work well in HFO-1234yf (R1234yf) systems. If the oil used for HFC-134a (R134a) systems (ND-OIL 8) is used in an HFO-1234yf (R1234yf) system, it will result in degradation of the refrigerant and deterioration of resin parts.

(2) When parts of the air conditioning system are removed, quickly block off any areas that are exposed to the outside air with plugs, vinyl tape, etc., as the oil used for HFO-1234yf (R1234yf) systems absorbs moisture easily.

(3) Do not allow the compressor oil to spray, as the oil used for HFO-1234yf (R1234yf) systems has harmful effects on acrylic resins.

(d) Compressor Oil (for HV Model)

(1) Always use ND-OIL 11 as the compressor oil.

NOTICE:

The oil used for HFC-134a (R134a) systems (ND-OIL 8) does not work well in HFO-1234yf (R1234yf) systems. If the oil used for HFC-134a (R134a) systems (ND-OIL 8) is used in an HFO-1234yf (R1234yf) system, it will result in degradation of the refrigerant and deterioration of resin parts.

(2) When parts of the air conditioning system are removed, quickly block off any areas that are exposed to the outside air with plugs, vinyl tape, etc., as the oil used for HFO-1234yf (R1234yf) systems absorbs moisture easily.

(3) Do not allow the compressor oil to spray, as the oil used for HFO-1234yf (R1234yf) systems has harmful effects on acrylic resins.

(e) Evacuation

(1) When evacuating the system, be sure to use a refrigerant recovery unit, refrigerant recycler and refrigerant charger that are compatible with HFO-1234yf (R1234yf) systems.

(f) Refrigerant Gas Leak Inspection

(1) Use a gas leak detector to check for refrigerant gas leaks.

HINT:

Be sure to use a gas leak detector that is compatible with HFO-1234yf (R1234yf) systems.

(2) Turn the engine switch (for Gasoline Model) or power switch (for HV Model) off when checking for refrigerant leaks.

HINT:

• If the engine is running when checking for leaks, the leaking gas will be diluted by the air from the fan and blower, making detection more difficult.

• If the air conditioning system is operating when checking for leaks, the refrigerant pressure in the system will decrease, making it harder for gas to leak.

• If the air conditioning system is operating when checking for leaks, the electronic gas leak detector may react to a sudden change in humidity due to the humid air coming from the drain cooler hose and a faulty judgment may be made.

PRECAUTIONS RELATED TO REMOVAL AND INSTALLATION OF PARTS

(a) If refrigerant gets in your eyes

(1) Do not rub your eyes with your hands or a cloth.

(2) Consult an eye doctor.

(b) Handling of Refrigerant (Container)

(1) Do not heat the container. If the container is directly heated or put into boiling water, the pressure inside the container will become abnormally high and the container may burst.

(2) Do not drop or strike the container.

(3) Do not bring the container anywhere near your face. Always wear eye protection.

(c) Pipe Installation (for Gasoline Model)

(1) Always use new O-rings.

HINT:

When removing an O-ring, use an object with a soft tip so as not to damage the piping.

(2) Apply a sufficient amount of compressor oil (ND-OIL 12) to the O-ring.

(3) Route the hoses in the way they are naturally shaped. Do not twist or forcibly bend the hoses.

(4) Do not use cloth gloves, etc. as fibers attached to O-rings can lead to refrigerant gas leaks.

(d) Pipe Installation (for HV Model)

(1) Always use new O-rings.

HINT:

When removing an O-ring, use an object with a soft tip so as not to damage the piping.

(2) Apply a sufficient amount of compressor oil (ND-OIL 11) to the O-ring.

(3) Route the hoses in the way they are naturally shaped. Do not twist or forcibly bend the hoses.

(4) Do not use cloth gloves, etc. as fibers attached to O-rings can lead to refrigerant gas leaks.

Replacement

REPLACEMENT

PROCEDURE

1. RECOVER REFRIGERANT FROM REFRIGERATION SYSTEM

(a) for Gasoline Model:

(1) Start the engine.

(b) for HV Model:

(1) Turn the power switch on (READY).

(c) Operate the compressor under the following conditions:

This causes most of the compressor oil from the various components of the A/C system to collect in the compressor.

HINT:

It is not necessary to operate the compressor if the A/C does not operate because of compressor lock, etc.

(d) for Gasoline Model:

(1) Stop the engine.

(e) for HV Model:

(1) Turn the power switch off.

(f) Recover the refrigerant from the A/C system using a refrigerant recovery unit.

HINT:

Use the refrigerant recovery unit in accordance with the manufacturer's instruction manual.

2. CHARGE AIR CONDITIONING SYSTEM WITH REFRIGERANT

HINT:

Charge the system with refrigerant in accordance with the manufacturer's instruction manual.

(a) Perform vacuum purging using a vacuum pump or appropriate equipment.

NOTICE:

Be sure to use a refrigerant recovery unit that is compatible with HFO-1234yf (R1234yf) systems.

(b) Charge the air conditioning system with refrigerant.

Refrigerant Type:

HFO-1234yf (R1234yf)

Standard Charge Amount:

NOTICE:

• Do not turn the A/C switch on before charging the air conditioning system with refrigerant. Doing so may cause the compressor to operate without refrigerant, resulting in overheating of the compressor.
• The refrigerant amount should be checked by quantity (weight).
• The graph above is shown for reference only.

HINT:

Ensure that sufficient refrigerant is available to recharge the system when using a refrigerant recovery unit. Refrigerant recovery units are not always able to recover 100% of the refrigerant from an air conditioning system.

3. WARM UP ENGINE (for Gasoline Model)

(a) Keep the A/C switch on for at least 2 minutes to warm up the compressor.

NOTICE:

To prevent damage to the compressor, be sure to warm up the compressor when turning the air conditioning on after removing and installing any air conditioning system lines (including the compressor).

4. WARM UP COMPRESSOR (for HV Model)

(a) Keep the A/C switch on for at least 2 minutes to warm up the compressor.

NOTICE:

To prevent damage to the compressor, be sure to warm up the compressor when turning the air conditioning on after removing and installing any air conditioning system lines (including the compressor).

5. INSPECT FOR REFRIGERANT LEAK

(a) After recharging the air conditioning system with refrigerant, inspect for refrigerant leaks using a halogen leak detector.

HINT:

Be sure to use a halogen leak detector that is compatible with HFO-1234yf (R1234yf) systems.

(b) Carry out the test under the following conditions:

• Turn the engine switch (for Gasoline Model) or power switch (for HV Model) off.
• Ensure good ventilation (the halogen leak detector may react to volatile gases which are not refrigerant, such as gasoline vapor and exhaust gas).
• Repeat the inspection 2 or 3 times.
• Measure the pressure to make sure that there is some refrigerant remaining in the air conditioning system.

  Pressure when the compressor is off: approximately 392 to 588 kPa (3.9 to 5.9 kgf/cm2, 57 to 85 psi)

(c) Using a halogen leak detector, inspect for refrigerant leaks from the air conditioning system.

*a Inspect for leak *b Halogen Leak Detector

(d) Bring the halogen leak detector close to the drain cooler hose with the detector power off, and then turn the detector on. HINT: After the blower motor has stopped, leave the cooling unit for more than 15 minutes. Bring the halogen leak detector sensor under the drain cooler hose. When bringing the halogen leak detector close to the drain cooler hose, make sure that the halogen leak detector does not react to volatile gases. If it is not possible to avoid interference from volatile gases, the vehicle should be lifted up to allow checking for leaks.

*1 Drain Cooler Hose *a Halogen Leak Detector

(e) If a refrigerant leak is not detected from the drain cooler hose, remove the blower motor control from the cooling unit. Insert the halogen leak detector sensor into the unit and check for leaks.

(f) Disconnect the pressure sensor connector and leave it for approximately 20 minutes. Bring the halogen leak detector close to the pressure sensor and check for leaks.

HINT:

When checking for leaks, the presence of oily dirt at a joint can indicate a leak.