Air Conditioning System (Diagnostics - Introduction): Overview Toyota Prius C I facelift

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1. PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE AUXILIARY BATTERY TERMINAL NOTE: When disconnecting the cable from the negative (-) auxiliary battery terminal, initialize the following system after the cable is reconnected. System Name See Procedure Power Door Lock Control System Refer to «INITIALIZATION [12/2013 - ]»(ref-651169-S40634195862014081900000)
2. IGNITION SWITCH EXPRESSIONS The type of ignition switch used on this model differs depending on the specifications of the vehicle. The expressions listed in the table below are used in this article. Expression Ignition Switch (Position) Power Switch (Condition) Ignition Switch off LOCK Off (Lock) Ignition Switch ACC ACC On (ACC) Ignition Switch ON (IG) ON (IG) On (IG) Ignition Switch ON (READY) ON (READY) On (Ready)
3. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED AREA OR NEAR AN OPEN FLAME TEXT IN ILLUSTRATION *a Charging Cylinder
4. ALWAYS WEAR EYE PROTECTION
5. 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.
6. NEVER HEAT CONTAINER OR EXPOSE CONTAINER TO AN OPEN FLAME
7. BE CAREFUL NOT TO DROP CONTAINER OR APPLY PHYSICAL SHOCKS TO IT
8. 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.
9. 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
10. 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.
11. DO NOT OPERATE COMPRESSOR WITH NO REFRIGERANT WARNING: Doing so may damage the inside of the compressor because the compressor parts always move regardless of whether the A/C system is turned on or off.
12. PRECAUTIONS TO BE OBSERVED WHILE SERVICING WARNING: Always use insulated 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-OIL 11 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-OIL 11 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 as much oil in the refrigerant cycle into the compressor as possible and replace it with ND-OIL 11 to increase the ND-OIL 11 ratio amount. Replace the main components (evaporator, condenser, and compressor) if a large amount of oil other than ND-OIL 11 enters the system. Failing to do so may cause electrical insulation performance to remain low, causing a DTC to be output.
13. SUPPLEMENTAL RESTRAINT SYSTEM (SRS) This vehicle is equipped with a 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 [12/2013 - ]»(ref-651349-S24445343132014081900000).
14. 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.

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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/output relationship similar to that of a human brain. Outlet Air Temperature Control Based on the temperature set by the temperature control dial, neural network control calculates outlet air temperature based on input signals from various sensors. Blower Control Controls the blower motor with fan sub-assembly in accordance with the airflow volume that has been calculated by 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 neural network control. 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 assembly calculates the target speed of the compressor based on the target evaporator temperature (which is calculated by the room temperature sensor, outside temperature sensor, 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 assembly 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 assembly 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. PTC Heater Control*1 When the hybrid system is operating (READY), and the blower with fan motor sub-assembly is turned on, the air conditioning amplifier assembly turns on the quick heater assembly if the conditions listed below are met. - Engine coolant temperature is below specified temperature. - Outside temperature is below specified temperature. - Tentative air mix damper opening angle is above the specified value (MAX HOT). Rear Defogger Control When the ignition switch is ON (IG) and the rear defogger switch is pushed, the system is activated to keep the defogger heater on for approx. 15 minutes. ECO Mode Control When the ECO mode switch (eco switch assembly) is turned on, the air conditioning amplifier assembly limits the air conditioning system performance. Diagnosis A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier detects a problem with the air conditioning system. *1: w/ Quick Heater Assembly
2. NEURAL NETWORK CONTROL In previous automatic air conditioning systems, the air conditioning amplifier assembly 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 assembly. The air conditioning amplifier assembly 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 outputs it 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 assembly controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control.
3. MODE POSITION AND DAMPER OPERATION Mode Position and Damper Operation TEXT IN ILLUSTRATION *a Air also blows out of the side registers *b Air also blows out of the side registers and defrosters *A for Cold Area Specification Vehicles - - 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 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 Air blows out of the center defroster, side defroster and side registers. FOOT / DEF E, H Air blows out of the front and rear footwell register duct, side registers and center defroster. FOOT E, G Air blows out of the side registers, front and rear footwell register duct. In addition, air blows out slightly from the center defroster and side defrosters. BI-LEVEL F, H Air blows out of the front and rear footwell register ducts, front center registers and side registers. FACE F, I Air blows out of the front center registers and side registers.
4. AIR OUTLETS AND AIRFLOW VOLUME Air Outlets and Airflow Volume TEXT IN ILLUSTRATION *A for Cold Area Specification Vehicles - - Indication Mode FACE FOOT DEF CTR SIDE C D A B FACE B/L FOOT F/D DEF The size of each circle o indicates the ratio of airflow volume.
5. 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 (ND-OIL 11) with a high level of insulation performance. Therefore, never use a compressor oil other than ND-OIL 11 type compressor oil or its equivalent. Along with the use of the hybrid system 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 an 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 assembly. 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, 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 assembly 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 assembly 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 assembly 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 assembly 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.
6. EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR) The evaporator temperature sensor (No. 1 cooler thermistor) 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 assembly.
7. BLOWER MOTOR WITH FAN SUB-ASSEMBLY The blower motor with fan sub-assembly has a built-in blower controller, and is controlled using duty control performed by the air conditioning amplifier assembly.
8. BUS CONNECTOR (AIR CONDITIONING HARNESS ASSEMBLY) BUS connectors are used in the wire harness that connects the servo motors to the air conditioning amplifier assembly. Each BUS connector has a built-in communication/driver IC which communicates with the air conditioning amplifier assembly, 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.
9. SERVO MOTOR The pulse pattern type servo motor consists of a printed circuit board and a servo motor. The printed circuit board has three contact points, and can transmit two ON-OFF signals to the air conditioning amplifier assembly based on the difference of the pulse phases. The BUS connector can detect the damper position and movement direction with these signals.
10. PTC HEATER (w/ QUICK HEATER ASSEMBLY) General The quick heater assembly is located above the heater core in the air conditioning unit. The quick heater assembly consists of a PTC element, aluminum fins, and brass plates. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit. TEXT IN ILLUSTRATION *1 Quick Heater Assembly *2 Brass Plate *3 PTC Element *4 Aluminum Fin Quick heater assembly operating conditions The quick heater assembly is turned on and off by the air conditioning amplifier assembly in accordance with the engine coolant temperature, ambient temperature, temperature setting, and electrical load (generator power ratio).
11. ECO MODE CONTROL Under the control of eco mode, the air conditioning amplifier assembly restricts the air conditioning system performance under specified conditions, thus improving fuel economy.
12. ROOM TEMPERATURE SENSOR (COOLER THERMISTOR) The room temperature sensor (cooler thermistor) detects the cabin temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier assembly.
13. AMBIENT TEMPERATURE SENSOR (THERMISTOR ASSEMBLY) The ambient temperature sensor (thermistor assembly) detects the outside temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier assembly.
14. SOLAR SENSOR The solar sensor detects (in the form of changes in the current that flows thought the built-in photo diode) the changes in the amount of sunlight and outputs these sunlight strength signals to the air conditioning amplifier assembly.
15. AIR CONDITIONING PRESSURE SENSOR The air conditioning pressure sensor detects the refrigerant pressure and outputs it to the air conditioning amplifier assembly in the form of voltage changes.

See also:
• REMOVAL [12/2013 - ]
• REMOVAL [12/2013 - ]