Air Conditioning (Diagnostics - Introduction): Overview Lexus HS I

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1. PRECAUTIONS WHEN USING TECHSTREAM When using the Techstream with the power switch off to troubleshoot: Connect the Techstream to the vehicle, and turn a courtesy light switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins. After all DTCs are cleared, check if the trouble occurs again 6 seconds after the power switch is turned on (IG).
2. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED AREA OR NEAR AN OPEN FLAME TEXT IN ILLUSTRATION *1 Charging Cylinder
3. ALWAYS WEAR EYE PROTECTION
4. 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.
5. NEVER HEAT CONTAINER OR EXPOSE CONTAINER TO OPEN FLAME
6. BE CAREFUL NOT TO DROP CONTAINER OR APPLY PHYSICAL SHOCKS TO IT
7. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH REFRIGERANT IN REFRIGERANT SYSTEM If there is not enough refrigerant in the A/C system, oil lubrication will be insufficient and the compressor may be damaged. Necessary care should be taken to avoid this.
8. 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.
9. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH REFRIGERANT If refrigerant is overcharged, it causes problems such as insufficient cooling, poor fuel economy, engine overheating, etc.
10. DO NOT OPERATE COMPRESSOR WITHOUT REFRIGERANT WARNING: Doing so may damage inside the compressor because the compressor parts always move regardless of whether the A/C system is turned on or off.
11. PRECAUTIONS TO BE OBSERVED WHILE SERVICING WARNING: Always use electric insulating gloves and remove the service plug grip before beginning inspection, as inspection of the A/C 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.
12. SUPPLEMENTAL RESTRAINT SYSTEM (SRS) This vehicle is equipped with an Supplemental Restraint System (SRS) such as the driver, front passenger, side and curtain shield airbags. Failure to carry out service operations in the correct sequence could cause the SRS to unexpectedly deploy during servicing, possibly leading to a serious accident. Before servicing (including removal or installation of parts, inspection or replacement), be sure to read the precautionary notices. Refer to «PRECAUTION»(ref-398246-S19065826952011051600000) .
13. GENERAL PRECAUTION While using battery voltage during inspection, do not bring the positive (+) and negative (-) tester probes too close to each other as a short circuit may occur.

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COMMUNICATION TABLE

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1. GENERAL The air conditioning system has the following controls. Control Outline Neural Network Control This control is capable of performing complex control by artificially simulating the information processing method of the nervous system of living organisms in order to establish a complex input or output relationship similar to that of a human brain. Micro Dust and Pollen Filter Mode Control Activated by the micro dust and pollen filter mode switch operation. Activated by the micro dust and pollen filter mode switch operation. 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 has been filtered by the clean air filter in order to remove pollen. Outlet Air Temperature Control Based on the temperature set by the temperature control switch, the neural network control calculates outlet air temperature based on input signals from various sensors. 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. Automatically increases the blower level when the defroster is on. When the rear seat blower is operated, the blower level for the rear seats is linked with the blower level for the front seat to achieve optimum airflow. Rear Blower Control Controls the rear 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. 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. In accordance with the engine coolant temperature, ambient air temperature, amount of sunlight, required blower, outlet temperature, and vehicle speed conditions, this control automatically switches the blower outlet to foot and defroster mode to prevent the windows from becoming fogged up when the ambient air temperature is low. Air Inlet Control Automatically controls the air inlet control damper to help achieve the calculated outlet air temperature that is required. Drives the air inlet control servo motor according to the operation of the air inlet control switch and moves the dampers to the fresh or recirculation position. Electric Inverter Compressor Control The air conditioning amplifier calculates the target speed of the compressor based on the target evaporator temperature (which is calculated by the room temperature sensor, outside temperature sensor, and the solar sensor) and the actual evaporator temperature that is detected by the evaporator temperature sensor in order to control the compressor speed. The air conditioning amplifier calculates the target evaporator temperature, which includes corrections based on the room temperature sensor, outside temperature sensor, the solar sensor, and evaporator temperature sensor. Accordingly, the air conditioning amplifier controls the compressor speed to an extent that would not inhibit the proper cooling performance or defogging performance. Turns the air conditioning ON automatically when the AUTO button is pressed when the blower is ON and the air conditioning is OFF. Decreases the compressor speed in order to ensure quietness when the vehicle is stopped or the engine is off. Defroster Control Defroster control logic is used to improve defroster performance. Rear Window Defogger Control Switches the rear defogger and outside 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. Heater Water Pump Control When the blower motor is on and the engine has been stopped by the hybrid vehicle control system control, the air conditioning amplifier turns on the heater water pump in accordance with the judgment of the air mix damper opening. 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 key that is used to operate the vehicle. The key-linked memory call control then recalls the settings if the key is used when the power switch is turned 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 button, and then the driver door is opened. Power switch is turned on (IG). ECO Mode Control When the ECO MODE switch is turned on, the air conditioning amplifier limits the air conditioning system performance. Plasmacluster Generator Control The Plasmacluster generator is controlled by the air conditioning amplifier assembly and operates when the Plasmacluster generator switch is pressed. Outside Temperature Indication Control Based on the signals from the ambient temperature sensor, this control calculates the outside temperature, this value is then corrected in air conditioning amplifier assembly, and shown on the multi information display or multi display. Diagnosis A Diagnostic Trouble Code (DTC) is stored in the memory when the air conditioning amplifier detects a problem with the air conditioning system. NEURAL NETWORK CONTROL In the previous automatic air conditioning systems, the air conditioning amplifier determined the required outlet air temperature and blower air volume in accordance with the calculation formula that has been obtained based on information received from the sensors. However, because the senses 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, or extremely uncomfortable in a hot climate. Therefore, as a technique for effecting a higher level of control, a neural network has been adopted 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. The air conditioning amplifier can then effect control to provide enhanced air conditioning comfort. The neural network control consists of neurons in the input layer, intermediate layer and output layer. The input layer neurons process the input data of the outside 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 these 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 controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control. MICRO DUST AND POLLEN FILTER MODE CONTROL When the micro dust and pollen filter switch is pressed, the micro dust and pollen filter mode control is activated. Then, the air vent 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 micro dust and pollen filter switch signal is received by the air conditioning amplifier assembly, the air conditioning amplifier assembly controls the A/C compressor, air inlet servo motor, air vent servo motor and blower motor as shown in the timing chart below. This control usually operates for approximately 3 minutes. However, when the outside temperature is low, it will operate for approximately 1 minute. After this control stops operating, the air conditioning amplifier assembly controls the air conditioning system using AUTO mode. MODE POSITION AND DAMPER OPERATION TEXT IN ILLUSTRATION *1 Center Defroster *2 Side Defroster *3 Fresh Air *4 Recirculated Air *5 Blower with Fan Motor Sub-assembly *6 Heater Radiator Unit Sub-assembly *7 No. 1 Cooler Evaporator Sub-assembly *8 Side Register *9 Front Footwell Register Duct *10 Rear Footwell Register Duct *11 Front Center Register *12 Cooer blower Assembly *13 Rear Center Register - - *a To Driver Side *b To Passenger Side Mode Position and Damper Operation FUNCTIONS OF MAIN DAMPERS Control Damper Operation Position Damper Position Operation Air Inlet Control Damper FRESH A Allows fresh air to enter. RECIRCULATION B Causes internal air to recirculate. Air Mix Control Damper MAX COLD to MAX HOT Temperature Setting C - D (C1 - D1) Varies the mixture ratio of warm air and cool air in order to regulate the temperature continuously between hot and cold. Air Outlet Control Damper DEF E, I Defrosts the windshield through the center defroster, side defrosters and side registers. FOOT/DEF E, H Defrosts the windshield through the center defroster, side defrosters and side registers while air is also blown out from the front and rear footwell register ducts. FOOT E, G Air blows out of the front and rear footwell register ducts, and side registers. In addition, air blows out slightly from the center defroster and side defrosters. BI-LEVEL F, H Air blows out of the front center register, rear center register, side registers and front and rear footwell register ducts. FACE F, I Air blows out of the front center register, rear center register and side registers. AIR OUTLETS AND AIRFLOW VOLUME Air Outlets and Airflow Volume Indication Mode FACE FOOT DEF CTR RR SIDE FR RR CTR SIDE A B C D E F G FACE B/L FOOT F/D DEF The size of each circle o indicates the ratio of airflow volume. MEMORY CALL CONTROL The air conditioning amplifier assembly stores the air conditioning settings for each memory number when the power switch is turned off. The main body ECU (multiplex network body ECU) converts the key ID code into a memory number, stores it and sends the converted signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly stores the memory number and air conditioning settings. When the doors are unlocked, the certification ECU (smart key ECU assembly) recognizes the key ID code and sends the key ID code to the main body ECU (multiplex network body ECU). Upon receiving the key ID code signal, the main body ECU (multiplex network body ECU) converts the signal into a memory number signal and sends it to the air conditioning amplifier assembly. Then the air conditioning amplifier assembly recalls the stored air conditioning settings based on the memory number signal when the power switch is turned on (IG). The following air conditioning system settings can be memorized: Setting Condition A/C Switch On or Off AUTO Switch On or Off Temperature Setting Driver Side LO, 16 to 30°C (61 to 86°F) or HI Front Passenger Side LO, 16 to 30°C (61 to 86°F) or HI Blower Fan Speed Level 1 to 7 Air Inlet Mode Fresh or Recirculate Air Outlet Mode Face, Bi-Level, Foot, Foot and Defroster or Defroster DUAL Switch On or Off HINT: Memory call control can be cancelled or re-enabled using the Techstream. When a new key is added, the key ID code registration is necessary. COMPRESSOR WITH MOTOR ASSEMBLY General HINT: In order to ensure the proper insulation of the internal high-voltage portion of the compressor and the compressor housing, this vehicle has adopted a compressor oil (ND11) with a high level of insulation performance. Therefore, never use a compressor oil other than the ND11 type compressor oil or its equivalent. Along with the installation of the hybrid unit on this vehicle, an electric inverter compressor that is driven by a motor is used. The basic construction and operation of this compressor are the same as the ordinary scroll compressor, except that it is driven by an electric motor. The Air Conditioning (A/C) inverter is integrated with the compressor. The electric motor is actuated by 3-phase alternating current (244.8 V) supplied by the A/C inverter. As a result, the air conditioning control system on this vehicle is actuated without depending on the operation of the engine, thus realizing a comfortable air conditioning system and low fuel consumption. Due to the use of an electric inverter compressor, the compressor speed can be controlled at the required speed calculated by the air conditioning amplifier. Thus, the cooling and dehumidification performance and power consumption have been optimized. Low-moisture permeation hoses are used for the suction and discharge hoses at the compressor in order to minimize the entry of moisture into the refrigeration cycle. The compressor uses high-voltage alternating current. If a short or open circuit occurs in the compressor wiring harness, the power management control ECU will cut off the A/C inverter circuit in order to stop the power supply to the compressor motor. Compressor Speed Control The air conditioning amplifier calculates the target compressor speed based on the target evaporator temperature (calculated from the temperature control switch, room temperature sensor, ambient temperature sensor, and solar sensor) and the actual evaporator temperature detected by the evaporator temperature sensor. Then, the air conditioning amplifier transmits the target speed to the power management control ECU. The power management control ECU controls the A/C inverter based on the target speed data in order to control the compressor to a speed that suits the operating condition of the air conditioning system. The air conditioning amplifier calculates the target evaporator temperature, which includes corrections based on the room temperature sensor, outside temperature sensor, solar sensor, and evaporator temperature sensor. Accordingly, the air conditioning amplifier controls the compressor speed to an extent that does not inhibit the proper cooling performance or defogging performance. As a result, comfort and low fuel consumption can be realized. HEATER WATER PUMP This vehicle uses an heater water pump for air conditioning. This provides a stable heater performance even if the engine is stopped because of a function of the hybrid control system. This vehicle uses a new type of electrical water pump in which the water flow resistance has been reduced. EVAPORATOR TEMPERATURE SENSOR The evaporator temperature sensor detects the temperature of the cool air immediately through the evaporator in the form of resistance changes, and outputs it to the air conditioning amplifier. PLASMACLUSTER (ION GENERATOR) CONTROL (w/ Plasmacluster Ion Generator) General: A Plasmacluster (ion generator) is provided inside the air duct of the side register on the driver seat side to improve the air quality and comfort in the cabin. This generator is controlled by the air conditioning amplifier and operates when the Plasmacluster generator switch is pressed. NOTE: The Plasmacluster (ion generator) uses a high voltage, which is hazardous. Therefore, if the Plasmacluster (ion generator) requires repairs, be sure to have them done at an authorized dealer. Do not apply any type of spray (such as a cleaning solvent or hair spray) or stick any foreign matter into the Plasmacluster ion outlet, as this could cause improper operation or a malfunction. After use, dust may accumulate around the side register on the driver seat side. If this occurs, press the OFF switch on the A/C control assembly to stop the blower motor before cleaning the area. It is normal for the Plasmacluster (ion generator) to emit a slight sound during operation. This sound is created when electrons collide with the electrode while Plasmacluster ions are being generated. HINT: Plasmacluster TM , plasmacluster, and plasmacluster ions are a trademark of the SHARP Corporation. Operation: The Plasmacluster (ion generator) produces positive and negative ions from the water molecules (H 2 O) and oxygen molecules (O 2 ) in the air, and emits them into the air. These ions reduce airborne germs. ECO MODE CONTROL Under the control of eco mode, the air conditioning amplifier restricts the air conditioning system performance under specified conditions, thus improving fuel economy Eco mode control is activated when the ECO MODE switch provided inside the integration control and panel sub-assembly is pressed, and then restricts the air conditioning system performance as described below. Control Outline Inside or Outside Air Switch Control Automatically switches the air inlet port to internal air circulation mode when the outside air temperature is equal to or higher than a predetermined temperature and reduces the power consumption Blower Level Control Sets the blower level in AUTO mode lower than normal, and suppresses the power consumption. PTC Heater Control Stops the operation of PTC heater assembly and suppresses the power consumption. Heating Restriction Control Changes the air outlet temperature by turning the ECO MODE switch on and off during heating and increases the amount of engine-off time when the ECO MODE switch is in the on state, thus improving fuel economy. Compressor Speed Restriction Control Restricts the maximum speed during cooling and reduces the power consumption. BLOWER MOTOR The PTC heater assembly is turned on and off by the air conditioning amplifier in accordance with the engine coolant temperature, ambient temperature, engine speed, temperature setting, and electrical load (generator power ratio). The rear blower motor is controlled by the air conditioning amplifier via a blower motor controller using duty control. BUS CONNECTOR (AIR CONDITIONING HARNESS) A BUS connector is used in the wire harness connection that connects the servo motor from the air conditioning amplifier. Each BUS connector has a built-in communication/driver IC which communicates with each servo motor connector, actuates the servo motor, and has a position detection function. This enables bus communication for the servo motor wire harness, for a more lightweight construction and a reduced number of wires. SERVO MOTOR The pulse pattern type servo motor consists of a printed circuit board and a servo motor. The printed circuit board has 3 contact points, and can transmit 2 ON-OFF signals to the air conditioning amplifier based on the difference of the pulse phases. The BUS connector can detect the damper position and movement direction with these signals. ROOM TEMPERATURE SENSOR (BUILT-IN HUMIDITY SENSOR) The room temperature sensor detects the cabin temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier. A humidity sensor function has been added to the room temperature sensor. By enabling the detection of humidity in the vehicle interior, this function optimizes the amount of dehumidification effort during the operation of the A/C system. As a result, the power consumption of the compressor has been reduced and a comfortable level of humidity has been realized in the vehicle interior. The humidity-sensing resistance film that is built into the humidity sensor absorbs and releases the humidity in the cabin. During the absorption and releasing processes, the humidity-sensing resistance film expands (during the absorption of humidity) and contracts (during drying). The clearance between the carbon particles in the humidity-sensing resistance film expands and contracts during absorption and drying, thus changing the resistance between the electrodes. The air conditioning amplifier determines the humidity in the cabin through the changes in the output voltage of the humidity sensor that are caused by the resistance between the electrodes. AMBIENT TEMPERATURE SENSOR The ambient temperature sensor detects the outside temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier. SOLAR SENSOR The solar sensor consists of a photo diode, 2 amplifier circuits for the solar sensor, and frequency converter circuit for the light control sensor. The solar sensor 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 the LH and RH sides (2 directions) and outputs these sunlight strength signals to the air conditioning amplifier. A/C PRESSURE SENSOR The A/C pressure sensor detects the refrigerant pressure and outputs it to the air conditioning amplifier in the form of voltage changes. COOLER BLOWER ASSEMBLY A compact cooler blower assembly and air ducts are located in the center console. This allows cool air to flow to the rear seats, achieving comfortable cooling performance for the rear seat passengers. The cooler blower assembly has a built-in blower motor control which is controlled by the air conditioning amplifier assembly. The cooler blower assembly has an integrated 3 A fuse in its wire harness to prevent over current. Cooler Blower Switch The blower level can be adjusted by turning the knob on the bottom of the rear center register. A cooler blower switch is provided on the airflow adjusting knob mechanism. The switch turns the cooler blower assembly blower motor on and off in conjunction with the airflow adjusting knob position.

See also:
• REMOVAL
• REMOVAL