Air Conditioning System (Service Information): Overview Lexus IS III

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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. Remove the cool air intake duct seal. Refer to «PROCEDURE - Step 1»(ref-665772-S07495103672014102400000) Read the manifold gauge pressure when the following conditions are met: Doors are fully open. The engine is idling. The A/C switch is on. The temperature is set to max cool. The blower speed is set to high. Temperature at the air inlet with recirculate selected is 30 to 35°C (86 to 95°F). Normally functioning air conditioning system GAUGE READING Pressure Side Refrigerant Volume Low 150 to 250 kPa (1.5 to 2.5 kgf/cm 2, 22 to 36 psi) High 1370 to 1570 kPa (14.0 to 16.0 kgf/cm 2, 199 to 228 psi) Abnormally functioning air conditioning system During operation, pressure on low pressure side cycles between normal and vacuum *a LO *b HI 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. Pressure is low on both low and high pressure sides *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. Pressure is low on both low and high pressure sides *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. 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. Pressure is too high on both low and high pressure sides *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. Pressure is too high on both low and high pressure sides *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 NOTE: 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. Pressure is too high on both low and high pressure sides *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. Pressure is too high on both low and high pressure sides 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. Gauge readings (Reference) *a Pressure on Low Pressure Side kPa (kgf/cm 2, psi) *b Pressure on High Pressure Side kPa (kgf/cm 2, psi) *c Blower High Zone *d Blower Low Zone Install the cool air intake duct seal. Refer to «PROCEDURE - Step 3»(ref-665772-S23921011662014102400000)

Scheme 56

1. RECOVER REFRIGERANT FROM REFRIGERATION SYSTEM Remove the cool air intake duct seal. Refer to «PROCEDURE - Step 1»(ref-665772-S07495103672014102400000) Start the engine. Operate the compressor under the conditions shown below: Item Condition Operating time 3 minutes or more Temperature setting Max cool Blower speed High Engine Idling A/C switch On 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. Stop the engine. 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 Perform vacuum purging using a vacuum pump or appropriate equipment. Charge the air conditioning system with refrigerant. Refrigerant Type HFC-134a (R134a) *a Standard Charge Amount *b Mean Value in Proper Range *c Overcharged *d High Pressure *e Sub-cool System *f Refrigerant Amount Standard Charge Amount 520 to 620 g (18.4 to 21.8 oz.) SST: 09985-20010 09985-02010 09985-02050 09985-02060 09985-02070 09985-02080 09985-02090 09985-02110 09985-02130 09985-02140 09985-02150 NOTE: Do not turn the A/C switch on before charging the air conditioning system with refrigerant. Doing so may cause the compressor to work 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 Keep the A/C switch on for at least 2 minutes to warm up the compressor. NOTE: To prevent damage to the compressor, be sure to warm up the compressor when turning the air conditioning on after removing and installing air conditioning system lines (including the compressor).
4. INSPECT FOR REFRIGERANT LEAK After recharging the air conditioning system with refrigerant, inspect for refrigerant leaks using a halogen leak detector. Carry out the test under the following conditions: Turn the engine switch 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/cm 2, 57 to 85 psi) Using a halogen leak detector, inspect for refrigerant leaks from the air conditioning system. *a Inspect for Leak *b Halogen Leak Detector Bring the halogen leak detector close to the drain cooler hose with the detector power off, and then turn the detector on. *1 Drain Cooler Hose *a Halogen Leak Detector 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. 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. 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. Install the cool air intake duct seal. Refer to «PROCEDURE - Step 3»(ref-665772-S23921011662014102400000)

Scheme 57

*A for 2WD - - *1 PIPING CLAMP *2 SUCTION PIPE SUB-ASSEMBLY *3 COOLER REFRIGERANT LIQUID PIPE A *4 LIQUID TUBE SUB-ASSEMBLY A *5 SUCTION HOSE *6 NO. 1 COOLER REFRIGERANT DISCHARGE HOSE *7 O-RING - - N*m (kgf*cm, ft.*lbf): Specified torque • Non-reusable part Compressor oil ND-OIL 8 or equivalent

Scheme 58

*A for AWD - - *1 PIPING CLAMP *2 SUCTION PIPE SUB-ASSEMBLY *3 COOLER REFRIGERANT LIQUID PIPE A *4 LIQUID TUBE SUB-ASSEMBLY A *5 SUCTION HOSE *6 NO. 1 COOLER REFRIGERANT DISCHARGE HOSE *7 O-RING - - N*m (kgf*cm, ft.*lbf): Specified torque • Non-reusable part Compressor oil ND-OIL 8 or equivalent

Scheme 59

1. RECOVER REFRIGERANT FROM REFRIGERATION SYSTEM See step 1
2. REMOVE HEADLIGHT ASSEMBLY LH (for HID Headlight) Refer to «REMOVAL [04/2013 - ]»(ref-665737-S12996065042014102400000)
3. REMOVE HEADLIGHT ASSEMBLY LH (for LED Headlight) Refer to «REMOVAL [04/2013 - ]»(ref-665737-S14734355282014102400000)
4. REMOVE PIPING CLAMP Install SST to the piping clamp as shown in the illustration. SST: 09870-00025 *1 Liquid Tube Sub-assembly A *2 Cooler Refrigerant Liquid Pipe A Hold the cooler refrigerant liquid pipe A and liquid tube sub-assembly A with each hand and push in SST with both thumbs. NOTE: Do not apply excessive force to the cooler refrigerant liquid pipe A or liquid tube sub-assembly A as they may bend. *a Push in Raise the stopper of SST and remove SST and the piping clamp together from the cooler refrigerant liquid pipe A. *1 Cooler Refrigerant Liquid Pipe A *a Stopper *b Pull off Remove the piping clamp from SST. Remove the cooler refrigerant liquid pipe A from the liquid tube sub-assembly A. Remove the 2 O-rings from the liquid tube sub-assembly A. NOTE: Seal the openings of the disconnected parts using vinyl tape to prevent entry of moisture and foreign matter.

See also:
• REMOVAL [04/2013 - ]
• REMOVAL [04/2013 - ]
• PROCEDURE - Step 4
• PROCEDURE - Step 1