Air Conditioning System (Diagnostics - Introduction): Overview Lexus GS IV

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1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED AREA OR NEAR AN OPEN FLAME TEXT IN ILLUSTRATION *a Charging Cylinder
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN YOUR EYES OR ON YOUR SKIN If liquid refrigerant gets in your eyes or on your skin: Wash the area with lots of cold water. WARNING: Do not rub your eyes or skin. Apply clean petroleum jelly to the skin. Go immediately to a hospital or see a physician for professional treatment.
4. NEVER HEAT CONTAINER OR EXPOSE THE CONTAINER TO AN OPEN FLAME
5. BE CAREFUL NOT TO DROP CONTAINER OR APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH REFRIGERANT IN REFRIGERANT SYSTEM If there is not enough refrigerant in the air conditioning system, oil lubrication will be insufficient and the compressor may be damaged. Necessary care should be taken to avoid this.
7. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE WHILE COMPRESSOR IS OPERATING Open and close only the low pressure valve. If the high pressure valve is opened, refrigerant flows in the reverse direction causing the charging cylinder to rupture. TEXT IN ILLUSTRATION *a Wrong *b Okay
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH REFRIGERANT If the system is overcharged with refrigerant, it causes problems such as insufficient cooling, poor fuel economy, engine overheating, etc.
9. DO NOT OPERATE COMPRESSOR WITH MOTOR ASSEMBLY WITH NO REFRIGERANT WARNING: Doing so may damage inside the compressor because the compressor parts always move regardless of whether the air conditioning system is turned on or off.
10. PRECAUTIONS TO BE OBSERVED WHILE SERVICING WARNING: Always use electrical insulating gloves and remove the service plug grip before beginning inspection, as inspection of the air conditioning system requires disconnecting high voltage connectors. NOTE: Only use ND-OIL11 for the electric inverter compressor of the air conditioning system. Using other compressor oils may be dangerous, as they may conduct electricity. Electrical insulation performance may decrease significantly if even a small amount of oil other than ND-OIL11 is used (or enters) in the refrigeration cycle, causing a DTC to be output. If other oil is accidentally used and a DTC is output, collect the compressor oil in the compressor and replace it with ND-OIL11 to increase the ND-OIL11 ratio amount. Replace the main components (evaporator, condenser, and compressor) if a large amount of oil other than ND-OIL11 enters the system. Failing to do so may cause electrical insulation performance to remain low, causing a DTC to be output.
11. GENERAL PRECAUTION While using the auxiliary battery during inspection, do not bring the positive (+) and negative (-) tester probes too close to each other as a short circuit may occur.
12. CHECK MEMORY CALL FUNCTION Memory registration. NOTE: Be sure to have all the transmitters prepared and available before performing registration. Lock the doors using a transmitter before performing registration. Sit in the driver seat while holding only the transmitter to be registered. Turn the power switch on (Ready) and turn on the air conditioning. Turn the power switch off. HINT: It is necessary to register each transmitter individually. Check memory call function. With the identification code of the transmitter registered in memory, check that the air conditioning operation is restored to its previous state when the turn the power switch on (Ready). HINT: The operation state differs depending on the registered transmitter.

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COMMUNICATION TABLE

1. *: w/ Rear Control Switch

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1. FUNCTION OF MAIN COMPONENTS The air conditioning system consists of the following parts: Component Function Multi-media Module Receiver Assembly, Multi Display*1, Accessory Meter Assembly*2, Remote Touch Allows operation and adjustment of the air conditioning system via switches. Rear Control Switch*3 Allows operation and adjustment of the rear air conditioning via switches. Air Conditioning Amplifier Assembly Transmits and receives data to and from the switches and sensors, and controls the air conditioning system. Compressor with Motor Assembly Performs suction, compression and discharge of refrigerant gas. Heater Accessory Assembly Controlled by the power management control ECU in accordance with signals from the air conditioning amplifier assembly. Blower with Fan Motor Sub-assembly Brush less motor is used to achieve a compact and lightweight assembly. Cooler Condenser Assembly A Multi-Flow-IV (MF-IV) sub-cool condenser is used to improve heat exchange efficiency. Heater Radiator Unit Sub-assembly A Straight Flow Aluminum-II (SFA-II) heater radiator is used for compactness and high performance. No. 1 Cooler Evaporator Sub-assembly A Revolutionary super-slim Structure (RS) type cooler evaporator sub-assembly is used for compactness and high performance. No. 1 Cooler Thermistor Detects the temperature of the cool air past the cooler evaporator sub-assembly and transmits the data to the air conditioning amplifier assembly. Thermistor Assembly Detects ambient temperature and outputs it to the air conditioning amplifier assembly. Cooler Thermistor Detects room temperature and outputs it to the air conditioning amplifier assembly. Air Conditioning Thermistor Assembly Detects glass temperature, glass surroundings temperature and glass humidity, and outputs them to the air conditioning amplifier assembly. Automatic Light Control Sensor Detects the changes in the amount of solar energy and outputs them to the air conditioning amplifier assembly. Quick Heater Assembly*4 Consists of a Positive Temperature Coefficient (PTC) element, an aluminum fin and a brass plate. Damper Servo Sub-assembly Receives the input of the operation signals from the air conditioning amplifier assembly, operates the motor, and opens and closes the dampers. Air Refiner Element Removes pollen, other particles and smell to provide a comfortable interior space. Air Conditioning Pressure Sensor Detects the refrigerant pressure and sends the data to the air conditioning amplifier assembly. Power Management Control ECU Receives the request signals from the air conditioning amplifier assembly, and controls the compressor with motor assembly and heater water pump assembly. ECM Receives the signals from the engine coolant temperature sensor and transmits them to the air conditioning amplifier assembly. Combination Switch Assembly Sends the ECO switch operation signal to the air conditioning amplifier assembly. *1: for 8 Inch *2: for 12.3 Inch *3: w/ Rear Control Switch *4: w/ PTC Heater
2. SYSTEM CONTROL The air conditioning system uses the following controls: Control Function Customizable*1 Neural Network Control This control is capable of effecting complex control by artificially simulating the information processing method of the nervous system of living organisms in order to establish a complex input/output relationship that is similar to a human brain. Standard (Not Customizable) Automatic Recirculation Control Automatically changes the air inlet mode to fresh air or recirculate mode in accordance with the level of harmful elements in the outside air, cabin temperature and outside temperature. Standard (Not Customizable) Changes the sensitivity of the smog ventilation sensor. *2 Micro Dust and Pollen Filter Mode Control Activated by the micro dust and pollen filter mode switch operation. Sends air which has passed through the air refiner element to the area around upper part of the bodies of the driver and front passenger. This air has been filtered by the air refiner element in order to remove pollen. Standard (Not Customizable) Outlet Air Temperature Control Based on the temperature set at the temperature control switch, the neural network control calculates the outlet air temperature based on the input signals from various sensors. Standard (Not Customizable) The temperature setting for the driver and front passenger is controlled independently in order to provide a separate vehicle interior temperature for the right and left sides of the vehicle. Thus, air conditioning control that accommodates occupant preferences has been achieved. Standard*3 (Not Customizable) The temperature setting for the driver, front passenger and rear passenger is controlled independently in order to provide a separate vehicle interior temperature for the right, left and rear sides of the vehicle. Thus, air conditioning control that accommodates occupant preferences has been achieved. Standard*4 (Not Customizable) Blower Control Controls the blower motor in accordance with the airflow volume that has been calculated by neural network control based on the input signals from various sensors. Standard (Not Customizable) Automatically increases the blower level when the defroster is on. *5 Air Outlet Control Automatically switches the air outlets in accordance with the outlet mode that has been calculated by neural network control based on the input signals from various sensors. Standard (Not Customizable) In accordance with the engine coolant temperature, outside air temperature, amount of sunlight, cabin air humidity, required blower, outlet temperature and vehicle speed conditions, this control automatically switches the blower outlet to FOOT/DEF mode to prevent the windows from becoming fogged when the outside air temperature is low. *5 Save Energy and Airflow Control Front seat air outlet mode is turned on when the driver is the only occupant in the cabin and the conditions are satisfied by the signals from each sensor. In addition, driver seat air outlet mode is turned on when the cabin condition stabilizes. Standard*4 (Not Customizable) Air Inlet Control Automatically controls the air inlet control damper to achieve the calculated outlet air temperature that is required. Standard (Not Customizable) Drives the servo motor in accordance with the operation of the air inlet control switch and moves the dampers to the FRESH or RECIRCULATION position. Standard (Not Customizable) Cooler Compressor Control Through the calculation of the target evaporator temperature based on various sensor signals, the air conditioning amplifier assembly optimally controls the discharge capacity by regulating the opening extent of the solenoid control valve. Standard (Not Customizable) Turns the air conditioning on automatically by pressing the AUTO switch when the blower is on and the air conditioning is off. *6 Evaporator Control When set to automatic, cooler compressor variable capacity operation is controlled to save power. When set to manual, cooler compressor variable capacity operation is controlled for maximum cooling to dehumidify air and prevent the windows from fogging up. *6 Memory Call Control Memorizes the last air conditioning settings when the power switch is turned from on (IG) to off in accordance with the ID code of the electrical key transmitter sub-assembly that is used to operate the vehicle. The memory call control then recalls the settings if the electrical key transmitter sub-assembly is used when the power switch is on (IG). This function operates when both of the following conditions are met: Inside of the outside door handle is touched or the driver door is unlocked using the unlock sensor, and then the driver door is opened. Power switch is on (IG). *6 Outside Temperature Indication Control Based on the signals from the thermistor assembly, this control calculates the outside temperature, this value is then corrected in air conditioning amplifier, and shown on the multi-information display. Standard (Not Customizable) ECO Drive Mode Control When set to ECO drive mode, the air conditioning amplifier assembly decreases the blower speed. Standard (Not Customizable) Diagnosis A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier assembly detects a problem with the air conditioning system. Standard (Not Customizable) HINT: *1: The customize setting can be turned on or off. For details, refer to the "Customize Parameters". Refer to «CUSTOMIZE PARAMETERS [03/2012 - ]»(ref-600428-S36548839722014022400000) . *2: Default setting is normal. *3: w/o Rear Control Switch *4: w/ Rear Control Switch *5: Default setting is on. *6: Default setting is automatic.
3. MODE POSITION AND DAMPER OPERATION Mode Position and Damper Operation TEXT IN ILLUSTRATION *A w/ Rear Control Switch - - *1 Recirculated Air *2 Air Inlet Control Door *3 Fresh Air *4 Air Refiner Element *5 Blower with Fan Motor Sub-assembly *6 No. 1 Cooler Evaporator Sub-assembly *7 Quick Heater Assembly (w/ PTC Heater) *8 Side Register (Front Passenger Side) *9 Center Register (Front Passenger Side) *10 Mode Control Door (for Front Passenger Footwell Register) *11 Front Footwell Register Duct (Front Passenger Side) *12 Rear Footwell Register Duct *13 Console Box Register *14 Front Footwell Register Duct (Driver Side) *15 Mode Control Door (for Driver Footwell Register) *16 Center Register (Driver Side) *17 Side Register (Driver Side) *18 Side Defroster *19 Center Defroster *20 No. 1 Heater Radiator Unit Sub-assembly *21 Inside-and-outside Dual Air Layer Control Door *22 Mode Control Door (for Defroster) *23 Air Mix Control Door *24 Mode Control Door (for Front Passenger Center and Side Register) *25 Mode Control Door (for Console Box Register and Rear Passenger Footwell Register Duct) *26 Mode Control Door (for Driver Center and Side Register) *27 Air Mix Control Door (for Driver Side Upper Layer) *28 Air Mix Control Door (for Driver Side Lower Layer) *29 Air Mix Control Door (for Rear Passenger) *30 Air Mix Control Door (for Front Passenger Lower Layer) *31 Air Mix Control Door (for Front Passenger Side Upper Layer) - - *a View from A *b To Center and Side Defrosters *c To Driver Side Center and Side Registers *d To Driver Side Footwell Register Duct *e To Console Box Register and Rear Footwell Register Duct *f To Front Passenger Side Footwell Register Duct *g To Front Passenger Side Center and Side Register - - Control Door Operation Position*1 Door Position Operation Air Inlet Control Door FRESH A2, B1 Brings in fresh air. RECIRCULATION A1, B2 Recirculates internal air. Inside-and-outside Dual Air Layer Control Door - (Auto Control) C1 - C2 Separates or integrates the upper layer and lower layer in response to the control conditions to control the inside-and-outside dual air layers. Air Mix Control Door MAX COLD to MAX HOT Temperature Setting D1 - D2*2 E1 - E2*3 F1 - F2*4 G1 - G2*5 H1 - H2*6 Varies the mixture ratio of warm air and cool air in order to continuously regulate the temperature between hot and cold. Mode Control Door (for All Seat Control Mode) FACE J1, K1, L1, M1, N3, O1, I3 Air blows out of the front center register, side register and console box register. BI-LEVEL J2, K2, L2, M2, N2, O2, I3 Air blows out of the front center register, side register, console box register and front and rear footwell register ducts. Air may blow out from the center defroster and side defroster depending on the cabin environment (I2). FOOT J3, K3, L3, M3, N2, O3, I3*7 or I2*8 Air blows out of the front footwell register and rear footwell register ducts. In addition, air blows out slightly from the front center register, side register and console box register. Air blows out slightly from the center defroster and side defroster when FOOT MODE is turned on by the automatic control. FOOT AND DEFROSTER J3, K3, L2, M2, N2, O2, I1 Defrosts the windshield through the center defroster and side defroster, while air is also blown out from the front footwell register and rear footwell register ducts. In addition, air blows out slightly from the front center register, side register and console box register. DEFROSTER J4, K4, L1, M1, O1, I1 Defrosts the windshield through the center defroster and side defroster ducts. Mode Control Door (for Front Seat Control Mode*9) FACE J1, K1, L1, M1, N1, O1, I3 Air blows out of the front center register and side register BI-LEVEL J2, K2, L2, M2, N1, O1, I3 Air blows out of the front center register, side register and front footwell register ducts. Air may blow out from the center defroster and side defroster depending on the cabin environment (I2). FOOT J3, K3, L3, M3, N1, O1, I3*7 or I2*8 Air blows out of the front footwell register. In addition, air blows out slightly from the front center register and side register. Air blows out slightly from the center defroster and side defroster when FOOT MODE is turned on by the automatic control. FOOT AND DEFROSTER J3, K3, L2, M2, N1, O1, I1 Defrosts the windshield through the center defroster and side defroster, while air is also blown out from the front footwell register. In addition, air blows out slightly from the front center register and side register. DEFROSTER J4, K4, L1, M1, N1, O1, I1 Defrosts the windshield through the center defroster and side defroster ducts. Mode Control Door (for Driver Seat Control Mode)*10 FACE J4, K1, L1, M1, N1, O1, I3 Air blows out of the driver side front center register and side register. BI-LEVEL J4, K2, L1, M2, N1, O1, I3 Air blows out of the driver side front center register, side register and front footwell register ducts. FOOT J4, K3, L1, M3, N1, O1, I3*7, I2*8 Air blows out of the driver side front footwell register. In addition, air blows out slightly from the front driver side center register and side register. Air blows out slightly from the center defroster and side defroster when FOOT MODE is turned on by the automatic control. FOOT AND DEFROSTER J4, K3, L1, M2, N1, O1, I1 Defrosts the windshield through the center defroster and side defroster, while air is also blown out from the driver side front footwell register. In addition, air blows out slightly from the front driver side center register and side register. HINT: *1: The table shows the left and right air outlets and rear seat air outlets operating simultaneously. On the models with 3-zone temperature control, each seat air outlet can be switched independently. *2: For driver side front register and side register *3: For front passenger side front register and side register *4: For driver side front footwell register *5: For console box register (w/ Rear Control Switch) and rear footwell register ducts *6: For front passenger side front footwell register *7: When FOOT MODE is selected by a manual operation. *8: When FOOT MODE is turned on by the automatic control or FOOT MODE is selected by a manual operation from except FOOT MODE. *9: When the rear seat air outlets are stopped by the left and right independent temperature control, or when front seat control mode is turned on through the save energy and airflow control of the 3-zone temperature control. *10: The driver seat control mode is turned on by the save energy and airflow control of the 3-zone temperature control.
4. AIR OUTLETS AND AIRFLOW VOLUME Air Outlets and Airflow Volume (for All Seat Control Modes) Indication Mode Face Footwell Defroster Center Side Rear Front Rear Center Side A B C D E F G FACE-U*1 - - - - FACE-L*1 - - FACE-R*1, *2 - - - - - BI-LEVEL*1, *2 *3 *3 FOOT-0*4 - - FOOT-D*1 FOOT-R*1, *2 FOOT-F*1 FOOT AND DEFROSTER *1, *2 DEFROSTER *1, *2 - - - - - HINT: The size of the circle o indicates the proportion of air flow volume. *1: When each mode is turned on by automatic control. In addition, -U, -L and -R in FACE mode are selected by the automatic control and -D, -R or -F in FOOT mode as well. *2: When each mode is selected by a manual operation. *3: Air may blow out from the defroster in response to the cabin temperature and moisture, and outside temperature conditions. *4: FOOT mode has been selected again by manual operation when FOOT mode has already been selected by automatic control or manual operation. Air Outlets and Airflow Volume (for Front Seat Control Modes) Indication Mode Face Footwell Defroster Center Side Rear Front Rear Center Side A B C D E F G FACE-U*1 - - - - - FACE-L*1 - - - - FACE-R*1, *2 - - - - - BI-LEVEL*1, *2 - - *3 *3 FOOT-0*4 - - - - FOOT-D*1 - - FOOT-R*1, *2 - - FOOT-F*1 - - FOOT AND DEFROSTER *1, *2 - - DEFROSTER *1, *2 - - - - - HINT: The size of the circle o indicates the proportion of air flow volume. *1: When each mode is turned on by automatic control. In addition, -U, -L and -R in FACE mode are selected by the automatic control and -D, -R or -F in FOOT mode as well. *2: When each mode is selected by a manual operation. *3: Air may blow out from the defroster in response to the cabin temperature and moisture, and outside temperature conditions. *4: FOOT mode has been selected again by manual operation when FOOT mode has already been selected by automatic control or manual operation. Air Outlets and Airflow Volume (for Driver Seat Control Modes [w/ Rear Control Switch]) Indication Mode Face (Only for Driver Side) Footwell (Only for Driver Side) Defroster Center Side Rear Front Rear Center Side A B C D E F G FACE-U*1 - - - - - FACE-L*1 - - - - FACE-R*1, *2 - - - - - BI-LEVEL*1, *2 - - *3 *3 FOOT-0*4 - - - - FOOT-D*1 - - FOOT-R*1, *2 - - FOOT-F*1 - - FOOT AND DEFROSTER *1, *2 - - HINT: The size of the circle o indicates the proportion of air flow volume. *1: When each mode is turned on by automatic control. In addition, -U, -L and -R in FACE mode are selected by the automatic control and -D, -R or -F in FOOT mode as well. *2: When each mode is selected by a manual operation. *3: Air may blow out from the defroster in response to the cabin temperature and moisture, and outside temperature conditions. *4: FOOT mode has been selected again by manual operation when FOOT mode has already been selected by automatic control or manual operation.

See also:
• DIAGNOSIS SYSTEM [03/2012 - ]
• REMOVAL [03/2012 - ]