AIR CONDITIONING SYSTEM DETAILS

  1. FUNCTION OF MAIN COMPONENTS

    1. The air conditioning consists of the following components:

      Component Function
      Front Air Conditioning Control Assembly Allows operation and adjustment of the air conditioning system via switches.
      Air Conditioning Amplifier Assembly Transmits and receives signals to and from the switches and sensors.
      Cooler Compressor Assembly A compact, lightweight, and low-noise 10-cylinder swash plate type cooler compressor (10S17) is used.
      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.
      Front Blower with Fan Motor Sub-assembly High magnetic force magnets and ball bearings are used to achieve a compact and lightweight assembly.
      No. 1 Cooler Evaporator Sub-assembly A Revolutionary super-slim Structure (RS) is used for compactness.
      Front No. 1 Cooler Thermistor Detects the temperature of the cool air past the No. 1 cooler evaporator sub-assembly and transmits the data to the air conditioning amplifier assembly.
      Cooler (Ambient Temperature Sensor) Thermistor Detects ambient temperature and outputs it to the air conditioning amplifier assembly via the combination meter assembly.
      Cooler (Front Room Temperature Sensor) Thermistor*1 Detects room temperature and outputs it to the air conditioning amplifier assembly.
      Cooler Expansion Valve Sprays the refrigerant in an atomized form.
      Quick Heater Assembly*2 Consists of a Positive Temperature Coefficient (PTC) element, an aluminium fin, and a brass plate.
      PTC Heater Relay*2 Adjusts the quick heater in 3 steps.
      Airmix Damper Servo Sub-assembly Receives the input of temperature setting dial signals via the air conditioning amplifier assembly, operates the motor, and opens and closes the airmix damper.
      Recirculation Damper Servo Sub-assembly Receives the input of the operation signals from the fresh-air/recirculation selector switch via the air conditioning amplifier assembly, operates the motor, and opens and closes the fresh-air/recirculation damper.
      Mode Damper Servo Sub-assembly Receives the input of the operation signals from the mode selector switch via the air conditioning amplifier assembly, operates the motor, and opens and closes the mode damper.
      Clean Air Filter Removes pollen and other particles to provide a comfortable interior space.
      ECM Receives the signals from the engine coolant temperature sensor and transmits them to the air conditioning amplifier assembly.
      Air Conditioning Pressure Sensor*3 Mounted on the high-pressure pipe, this sensor controls the cooler compressor assembly.
      Air Conditioning Pressure Switch*4 Mounted on the high-pressure pipe, this switch controls the cooler compressor assembly.
      Engine Coolant Temperature Sensor Detects the engine coolant temperature and transmits it to the ECM.

      • *1: Models with automatic air conditioning

      • *2: Models with quick heater assembly

      • *3: Models with 1KD-FTV engine or dual air conditioning

      • *4: Except models with 1KD-FTV engine or dual air conditioning

    2. The rear air conditioning consists of the following parts:

      Component Function
      Rear Air Conditioning Control Assembly Allows operation and adjustment of the air conditioning system via switches.
      Cooler (Rear Room Temperature Sensor) Thermistor Detects rear room temperature and outputs it to the air conditioning amplifier assembly.
      Air Conditioning Amplifier Assembly Transmits and receives signals to and from the switches and sensors.
      Rear Evaporator Sub-assembly A Revolutionary super-slim Structure (RS) is used for compactness.
      Rear No.1 Cooler Thermistor Detects the temperature of the cool air past the rear evaporator sub-assembly and transmits the data to the air conditioning amplifier assembly.
      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.
      Rear Blower with Fan Motor Sub-assembly High magnetic force magnets and ball bearings are used to achieve a compact and lightweight assembly.
      Airmix Damper Servo Sub-assembly Receives the input of temperature setting dial signals via the air conditioning amplifier assembly, operates the motor, and opens and closes the airmix damper.
      Mode Damper Servo Sub-assembly Receives the input of the operation signals from the mode selector switch via the air conditioning amplifier assembly, operates the motor, and opens and closes the mode damper.

  2. SYSTEM CONTROL

    1. The air conditioning system uses following controls:

      Control Outline Air Conditioning Type
      Manual Automatic
      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)
      Pollen Removal Mode Control Activated by the pollen removal mode switch operation. Switches the air outlet to the FACE mode. Sends air which has passed through the clean air filter to the area around the upper part of the bodies of the driver and front passenger. This air is filtered by the clean air filter 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 side of the vehicle. Thus, air conditioning control that accommodates occupant preferences has been realized. - Standard (Not Customizable)
      Blower Control Controls the blower motor in accordance with the airflow volume that has been calculated by the neural network control based on the input signals from various sensors. - Standard (Not Customizable)
      Automatically increases the blower level when the defroster is on. - Default Setting is On
      Air Outlet Control Automatically switches the air outlets in accordance with the outlet mode that has been calculated by the neural network control based on the input signals from various sensors. - Standard (Not Customizable)
      Air Inlet Control* Automatically controls the air inlet control damper in accordance with the airflow volume that has been calculated by the neural network control. - Standard (Not Customizable)
      Automatically switches between fresh-air/recirculation in conjunction with the set temperature while automatic air conditioning is operating. - Default Setting is On
      Cooler Compressor Control This control turns off the magnetic clutch of the cooler compressor assembly when the blower motor is turned off at the time the engine coolant temperature is below a predetermined value, an abnormal refrigerant pressure has been input, or the discharge temperature of the evaporator is below a predetermined value. - Standard (Not Customizable)
      When the DEF mode switch is turned on, the magnetic clutch relay is activated automatically to engage the cooler compressor assembly. Also, when the blower is turned off, and the front defroster switch is turned on, the blower will turn on in the automatic control condition. - Standard (Not Customizable)
      Turns the air conditioning on automatically by pressing the AUTO button when the blower is on and the air conditioning is off. - Default Setting is On
      Rear Window Defogger Control

      • Switches the rear defogger and outer rear view mirror heaters on for 15 minutes when the rear defogger button is pressed.

      • Switches them off if the button is pressed while they are operating.

      		 Standard (Not Customizable) Standard (Not Customizable)
      Self-diagnosis Checks the sensors in accordance with the operation of the air conditioning switches, then displays a Diagnosis Trouble Code (DTC) on the clock to indicate if there is a malfunction or not (sensor check function). - Standard (Not Customizable)

      • *: Except models for G.C.C. countries

    2. Neural Network Control

      1. In the previous automatic air conditioning system, the air conditioning amplifier assembly determined the required outlet air temperature and blower air volume in accordance with a calculation formula that had been obtained based on information received from the sensors. However, because the sensors of a person are rather complex, a given temperature is sensed differently, depending on the environment in which the person is situated. For example, a given amount of solar radiation can feel comfortably warm in a cold climate, but extremely uncomfortable in a hot climate. Therefore, as a technique for effecting a high level of control, a neural network is used in the automatic air conditioning system. With this technique, the data that has been collected under varying environmental conditions is stored in the air conditioning amplifier assembly, which effects control to provide enhanced air conditioning comfort.

      2. The neural network control consists of neurons in an input layer, an intermediate layer, and an output layer. The input layer neurons process the input data of the ambient temperature, the amount of sunlight, and the room temperature based on the outputs of the switches and sensors, and output them to the intermediate layer neurons. Based on this data, the intermediate layer neurons adjust the strength of the links among the neurons. The sum of this data is then calculated by the output layer neurons in the form of the required outlet temperature, solar correction, target airflow volume, and outlet mode control volume. Accordingly, the air conditioning amplifier assembly controls the servo motors and blower with fan motor sub-assembly in accordance with the control volumes that have been calculated by the neural network control.

        A00JAQAE01

    3. Quick Heater Control

      1. The on/off function of the quick heater assembly is controlled by the air conditioning amplifier assembly in accordance with the engine coolant temperature, engine speed, air mix setting, and electrical load (generator power ratio).

      2. For example, the heating value of the operating quick heater assemblies varies depending on the engine coolant temperature, as shown in the graph below:

        A00JBAFE04

    4. Viscous Type Power Heater

      1. This system complements the conventional heater (heater core) when the engine coolant temperature is low, and accelerates the engine warm up by using the viscous power heater unit driven by the engine. Thus, heater performance improvement in cold conditions is successfully achieved.

      2. The power heater, which is located on top of the engine, is driven by a drive belt. Pressing the power heater switch provided in the instrument panel engages the magnetic clutch, causing the rotor in the power heater to rotate and the silicon oil to mix. The sheer heat that is thus generated heats the coolant.

    5. Pollen Removal Mode Control

      1. When the pollen removal mode switch is pressed, the pollen removal mode control is activated. Then, the air outlet is switched to the FACE mode and recirculated pollen-free air flows in the area around the upper part of the bodies of the driver and front passenger.

        • When the pollen removal mode switch signal is input to the air conditioning amplifier assembly, the air conditioning amplifier assembly controls the cooler compressor assembly, recirculation damper servo sub-assembly, mode damper servo sub-assembly and blower with fan motor sub-assembly as shown in the timing chart below.

        • This control usually operates for approximately 3 minutes. However, when the ambient temperature is low [5°C (41°F) maximum], it will operate for approximately 1 minute.

        • After this control stops operating, the air conditioning amplifier assembly automatically returns to the mode it was in just before the pollen removal mode switch was pressed.

        A00JAUAE01

  3. CONSTRUCTION

    1. Air Conditioning Control Assembly

      1. Manual Air Conditioning Control Assembly

        • 5 air outlet modes are provided on the control panel on the models with manual air conditioning.

        A00JAMV

      2. Automatic Air Conditioning Control Assembly

        • An automatic air conditioning control assembly with Liquid Crystal Display (LCD) is used to ensure excellent visibility.

        • Temperature control can be set independently for the driver and front passenger sides. For this reason, temperature control switches for the driver and front passenger are provided on the air conditioning control assembly.

        A00JBE6

      3. Rear Manual Air Conditioning Control Assembly

        • A rotary switch type rear manual air conditioning control assembly is used, and is located on the rear console panel.

        A00JBEW

      4. Rear Automatic Air Conditioning Control Assembly

        • A rear automatic air conditioning control assembly with Liquid Crystal Display (LCD) is used to ensure excellent visibility.

        A00JBFO

    2. Air Conditioning Unit

      1. The air conditioning unit consists of the No. 1 cooler evaporator sub-assembly, heater radiator unit sub-assembly, servomotors, front No. 1 cooler thermistor, quick heater assembly* and blower with fan motor sub-assembly.

        • *: Models with quick heater assembly

      2. A semi-central location air conditioning unit, in which the No. 1 cooler evaporator sub-assembly and heater radiator unit sub-assembly are placed in the vehicle's longitudinal direction, is used.

        A00JBCOE01
        Text in Illustration
        *1 No. 1 Cooler Evaporator Sub-assembly *2 Heater Radiator Unit Sub-assembly
        A00JB85 Front - -

    3. No. 1 Cooler Evaporator Sub-assembly

      1. A Revolutionary super-slim Structure (RS) evaporator is used. By placing the tanks at the top and the bottom of the No. 1 cooler evaporator sub-assembly and by using a micropore tube construction, the following effects have been achieved:

        • Heat exchanging efficiency is ensured.

        • The temperature distribution is made uniform.

        • The No. 1 cooler evaporator sub-assembly has been made thinner.

        A00JB99E01
        Text in Illustration
        *1 Tank *2 Micropore Tube
        *3 Cooling Fin - -

    4. Front No. 1 Cooler Thermistor

      1. The front No. 1 cooler thermistor detects the temperature of the cool air immediately past the No. 1 cooler evaporator sub-assembly in the form of resistance changes, and outputs it to the air conditioning amplifier assembly.

    5. Heater Radiator Unit Sub-assembly

      1. This heater radiator unit sub-assembly has been made more compact and performance has been improved by making the core section finer and improving the shapes of the tank section and flow section. Also, the environment has been considered. By using aluminum as the material, the amount of the environmental burden disposal (lead) has been reduced.

        A00JBC2

    6. Blower with Fan Motor Sub-assembly

      1. The blower with fan motor sub-assembly has a built-in blower controller, and is controlled using duty control performed by the air conditioning amplifier assembly.

    7. Bus Connector

      1. The bus connector has a built-in communication/driver IC, which communicates with each servomotor connector, actuates the servomotor, and has a position detection function. This enables bus communication for the servomotor wire harness to achieve a more lightweight construction and a reduced number of wires.

        A00JAZTE01
        A00JAPFE01

    8. Servomotor

      1. In contrast to the previous type that detects the position by way of a potentiometer voltage, the pulse pattern type servomotor detects the relative position by way of the 2-bit on/off signals.

      2. The forward and reverse revolutions of this motor are detected by way of 2 phases, A and B, which output 4 types of patterns. The air conditioning amplifier assembly counts the number of pulse patterns in order to determine the stopped position.

        A00JAWFE01

    9. Quick Heater Assembly

      1. The quick heater assembly is located above the heater radiator unit sub-assembly in the air conditioning unit.

      2. The quick heater assembly consists of a PTC element, an aluminum fin, and a brass plate. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit.

        A00JB4VE01
        Text in Illustration
        *1 Brass Plate *2 PTC Element
        *3 Aluminum Fin - -

    10. Clean Air Filter

      1. A pollen removal type clean air filter is used to remove dust, pollen, and other micron particles from air entering from outside the vehicle to provide a comfortable cabin of clean air. The clean air filter is installed in the upper section of the blower fan.

        A00JB12E01
        Text in Illustration
        *1 Clean Air Filter - -

        Tech Tips

        See the table below regarding the replacement intervals for the high efficiency type clean air filter. Replace the clean air filter after the ignition switch (engine switch*) has been turned off.

        *: Models with entry and start system

        Condition Destination
        Europe G.C.C. Countries, Australia and General Countries
        Normal Conditions Cleaning 15000 km (9000 miles) 15000 km (9000 miles)
        Replacement 30000 km (18000 miles) 30000 km (18000 miles)
        Dusty Conditions Cleaning 7500 km (5000 miles) 5000 km (3000 miles)
        Replacement 15000 km (9000 miles) 10000 km (6000 miles)

    11. Condenser Assembly

      1. The sub-cool condenser is used. This is a multi-flow condenser consisting of 3 portions: a condensing portion, a super-cooling portion and a gas-liquid separator (modulator) all integrated together. This condenser assembly uses a sub-cool cycle for its cooling cycle system to improve heat-exchanging efficiency.

      2. In the sub-cool cycle, after the refrigerant passes through the condensing portion of the condenser assembly, both the liquid refrigerant and the gaseous refrigerant that could not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the No. 1 cooler evaporator sub-assembly in an almost completely liquefied state.

        A00JBDGE01
        Text in Illustration
        *1 Condensing Portion *2 Modulator
        *3 Desiccant *4 Filter
        *5 Super-cooling Portion - -
        A00JB85 Gaseous Refrigerant A00JBCU Liquid Refrigerant

        Tech Tips

        The point at which the air bubbles disappear in the refrigerant of the sub-cool cycle is lower than the proper amount of refrigerant with which the system must be filled. Therefore, if the system is recharged with refrigerant based on the point at which the air bubbles disappear, the amount of refrigerant would be insufficient. As a result, the cooling performance of the system will be affected. If the system is overcharged with refrigerant, this will also lead to reduced performance. For the proper method of verifying the amount of the refrigerant and to recharge the system with refrigerant, refer to the corresponding Repair Manual for this model.

        A00JBF6E01

    12. Cooler Compressor Assembly

      1. A compact, lightweight, and low-noise 10-cylinder swash plate type cooler compressor (10S17) is used.

        A00JAWA

    13. Cooler (Front Room Temperature Sensor) Thermistor

      1. The cooler (front room temperature sensor) thermistor detects the front room temperature based on changes in the resistance of its built-in thermistor. This signal is used by the air conditioning amplifier assembly.

    14. Cooler (Rear Room Temperature Sensor) Thermistor

      1. The cooler (rear room temperature sensor) thermistor detects the rear room temperature based on changes in the resistance of its built-in thermistor. This signal is used by the air conditioning amplifier assembly.

    15. Cooler (Ambient Temperature Sensor) Thermistor

      1. The cooler (ambient temperature sensor) thermistor detects the ambient temperature based on changes in the resistance of its built-in thermistor. This signal is used by the air conditioning amplifier assembly.

    16. Cooler (Solar Sensor) Thermistor

      1. The cooler (solar sensor) thermistor consists of a photo diode, 2 amplifier circuits for the cooler (solar sensor) thermistor, and a frequency converter circuit for the automatic light control sensor.

      2. The cooler (solar sensor) thermistor detects (in the form of changes in the current that flows through the built-in photo diode) the changes in the amount of sunlight from its LH and RH sides (2 directions) and outputs these sunlight strength signals to the air conditioning amplifier assembly.

        A00JAPXE05

    17. Sub-cool Accelerator Type Tube

      1. A sub-cool accelerator type tube is used to enhance air conditioning cooling performance. It functions as a heat exchanger by making use of the temperature difference between the gaseous refrigerant and liquid refrigerant.

      2. The sub-cool accelerator type tube has a double-pipe construction. Helical grooves are embossed into the outer wall of the inner tube. Low-temperature and low-pressure gaseous refrigerant passes through the inner tube. High-temperature and high-pressure liquid refrigerant circulates between the inner tube and outer tube in the gap created by the grooves. Because of the temperature difference, heat exchange occurs.

      3. The high-temperature and high-pressure liquid refrigerant circulate along the helical grooves causing the refrigerant to remain in contact with the outer wall of the inner tube for a longer period of time. This achieves an ample exchange of heat.

      4. By lowering the temperature of the refrigerant that has passed through the cooler condenser, more liquid refrigerant is supplied to the evaporator and the evaporator is also kept cooler. This enables an enhanced air conditioning cooling effect.

        A00JASHE01

    18. Cool Box

      1. The cool box consists primarily of a cool box amplifier, an evaporator (for cool box), a cool box blower motor, a cool box switch, and an expansion valve. The connected refrigerant circuit of the front air conditioning cools the cool box.

        A00JAWSE01
        Text in Illustration
        *1 Condenser Assembly *2 Cooler Compressor Assembly
        *3 Check Valve *4 No. 1 Cooler Evaporator Sub-assembly
        *5 No. 1 Cooler Evaporator Sub-assembly No.2 *6 Cool Box
        *7 Magnetic Valve *8 Cooler Expansion Valve

  4. OPERATION

    1. Front Air Conditioning Mode Position and Damper Operation

      A00JB6WE01
      Control Damper Operation Position Damper Position Operation
      Air Inlet Control Damper FRESH A Brings in fresh air.
      RECIRC B Recirculates internal air.
      Air Mix Control Damper MAX COLD to MAX HOT Temp. Setting

      E - D - C

      (E' - D' - C')

      		 Varies the mixture ratio of the cold air and the hot air in order to regulate the temperature continuously from HOT to COLD.
      Max Cool Damper Max Cool V Open in the MAX COOL position
      Except Max Cool W Closed in all position except MAX COOL position
      Max Hot Damper Max Hot Y Open in the MAX HOT position
      Except Max Hot X Closed in all position except MAX HOT position
      Mode Control Damper A00JB6X DEF H, I, S, U, X Defrosts the windshield through the center defroster, and side defroster.
      A00JAP9 FOOT / DEF Max Hot Position H, K, R, T, W, Y Defrosts the windshield through the center defroster, side defroster, front and rear footwell register ducts while air is also blown out from the front and rear center registers and side register.
      Except Max Hot Position H, M, Q, T, X
      A00JAVF FOOT Max Hot Position H, M, P, T, W, Y Air blows out of the front and rear footwell register duct. In addition, air blows out slightly from the center register, side register, rear center register*, center defroster and side defroster.
      Except Max Hot Position H, M, O, T, X
      A00JB1V BI-LEVEL G, L, N, T, X Air blows out of the front and rear center registers*, side register, and front and rear footwell register ducts.
      A00JBFF FACE Auto Mode F, J, N, T, X Air blows out of the front and rear center registers*, and side register.
      Manual Mode F, I, N, T, X

      • *: Models with single air conditioning

    2. Rear Air Conditioning Mode Position and Damper Operation

      A00JB6SE01
      Control Damper Operation Position Damper Position Operation
      Mode Control Door A00JBFF FACE A Air blows out of the rear roof side register.
      A00JB1V BI-LEVEL B Air blows out of the rear roof side register and the rear footwell register.
      A00JAVF FOOT C Air blows out of the rear footwell register.
      Air Mix Control Damper MAX COLD to MAX HOT Temp. Setting D - E Varies the mixture ratio of the cold air and the hot air in order to regulate the temperature continuously from HOT to COLD.

    3. Front Air Outlets and Airflow Volume (Models with Automatic Air Conditioning)

      A00JB47E01
      Indication Mode Section A B C D E F
      Auto Manual Center Side Front Footwell Rear Face*1 Rear Footwell Defroster
      A00JBFF FACE-U ● ● A00JAQQ A00JAQQ - A00JAQW - -
      FACE-L*2 ● - A00JAQ4 A00JAQ4 A00JB28 A00JAQW A00JAQZ -
      A00JB1V BI-LEVEL ● ● A00JAQW A00JAQW A00JAQW A00JAOX A00JAWV -
      A00JAVF FOOT ● ● A00JAOX A00JAOX A00JAQQ A00JAQZ A00JB1H A00JAQW
      A00JAP9 FOOT/DEF ● ● A00JAQZ A00JAOX A00JAQ4 A00JAQZ A00JAQW A00JAQ4
      A00JB6X DEF - ● - - - - - A00JAQQ

      Tech Tips

      *1: Models with single air conditioning

      *2: The airflow volume is set to be greater than that of FACE-U mode.

      The size of the circle ○ indicates the proportion of airflow volume.

    4. Front Air Outlets and Airflow Volume (Models with Manual Air Conditioning)

      A00JB47E01
      Indication Mode A B C D E F
      Center Side Front Footwell Rear Face* Rear Footwell Defroster
      A00JBFF FACE A00JAQQ A00JAQQ - A00JAWV - -
      A00JB1V BI-LEVEL A00JAQW A00JAQW A00JAQW A00JAOX A00JAWV -
      A00JAVF FOOT A00JB28 A00JB28 A00JAQQ A00JAQZ A00JB1H A00JAWV
      A00JAP9 FOOT/DEF A00JAQZ A00JB28 A00JB1H A00JAQZ A00JAQW A00JAQ4
      A00JB6X DEF - - - - - A00JAQQ

      Tech Tips

      *: Models with single air conditioning

      The size of the circle ○ indicates the proportion of airflow volume.

    5. Rear Air Outlets and Airflow Volume

      A00JAOQE01
      Indication Mode A B
      A00JBFF FACE A00JAQQ -
      A00JB1V BI-LEVEL A00JAQW A00JAOX
      A00JAVF FOOT - A00JAQQ

  5. DIAGNOSIS

    1. Diagnostic Trouble Code (DTC)

      1. The air conditioning amplifier assembly has a self-diagnosis function. It stores any operation failures in the air conditioning system memory in the form of DTCs. For details, refer to the corresponding Repair Manual for this model.