Air Conditioning System (Diagnostics - Introduction) (Plug-In): Overview Toyota Prius Plug-in

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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»(ref-553290-S07508891342013051700000)
2. 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.
3. 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 malfunction occurs again 6 seconds after the power switch is turned on (IG).
4. DO NOT HANDLE REFRIGERANT IN ENCLOSED AREA OR NEAR OPEN FLAME TEXT IN ILLUSTRATION *1 Charging Cylinder
5. ALWAYS WEAR EYE PROTECTION
6. 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.
7. NEVER HEAT CONTAINER OR EXPOSE THE CONTAINER TO AN OPEN FLAME
8. BE CAREFUL NOT TO DROP CONTAINER OR APPLY PHYSICAL SHOCKS TO IT
9. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH REFRIGERANT IN AIR CONDITIONING 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.
10. 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 will flow in the reverse direction causing the charging cylinder to rupture.
11. 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.
12. DO NOT OPERATE COMPRESSOR WITHOUT 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.
13. 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 the compressor oil in the compressor 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.
14. 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»(ref-553460-S10830612362013051700000).
15. PRECAUTIONS WHEN WORKING Vehicles with the remote climate control system have the following risks that it is necessary to be aware of when performing repairs. Therefore, make sure to handle the key (electrical transmitter) carefully so that the remote climate control system is not operated unexpectedly. RISKS The electrical fan and other items in the engine compartment may operate resulting in various hazards. The wipers may operate if the wiper switch is in the on position when the remote climate control system is activated. If this occurs, there is the potential for damage to the glass, wipers or injury. When the light control switch is in the tail, head or AUTO position, the headlights may turn on. Short circuits may occur if electrical inspections are being performed when the remote climate control system is turned on, because the IG circuit is powered at this time. WARNING: Failure to take proper care with the key (electrical transmitter) may cause the system to be accidentally operated. This can lead to an accident and damage to parts or a serious injury. HINT: Make sure to store the key (electrical transmitter) in a box with the switch side facing up, and place the box where it can be monitored so that no one cannot operate the remote A/C switch.

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1. Air Conditioning System COMMUNICATION TABLE Sender Receiver Signal Communication Line Air conditioning amplifier assembly ECM Heater idle up request signal CAN ECO switch information signal Prior A/C control request signal Cooling fan motor driving request signal Refrigerant gas pressure sensor signal Ambient temperature signal Air conditioning amplifier assembly Power management control ECU Heater idle up request signal CAN ECO switch information signal Prior A/C control request signal Water pump ON/OFF request signal Inverter STB ON/OFF request signal Electrical compressor start signal Electrical compressor target revolutions signal A/C control state signal Air conditioning amplifier assembly Air conditioning control assembly Ambient temperature indicator signal LIN MODE indication signal Blower level indication signal Set temperature indication signal Combination meter assembly (No. 3 meter circuit plate) Air conditioning amplifier assembly Vehicle speed signal CAN Air conditioning amplifier assembly Combination meter assembly (No. 3 meter circuit plate) REC indicator signal CAN FRS indicator signal Driver temperature display signal ECM Air conditioning amplifier assembly Engine speed signal CAN Engine coolant temperature signal Power management control ECU Air conditioning amplifier assembly Shift position P signal CAN Shift position R signal Shift position N signal A/C inverter main power supply voltage signal A/C inverter output signal A/C inverter internal power source malfunction signal STB wire short signal State of STB signal A/C inverter temperature information signal Compressor start flag signal Compressor humidity control start flag signal A/C motor revolution signal A/C motor current request signal Air conditioning control assembly Air conditioning amplifier assembly AUTO switch signal LIN A/C switch signal Fr DEF switch signal Rr DEF switch signal MODE switch signal REC/FRS switch signal Micro dust and pollen filter mode switch signal Blower switch signal (FAN+, FAN-, OFF) Set temperature switch signal (UP, DOWN)
2. Remote Climate Control System COMMUNICATION TABLE Sender Receiver Signal Communication Line Key (electrical transmitter) Certification ECU (smart key ECU assembly) Remote climate control system activation request signal Radio waves Remote climate control system stop request signal Certification ECU (smart key ECU assembly) Main body ECU (multiplex network body ECU) Remote climate control system activation request signal CAN Remote climate control system stop request signal Main body ECU (multiplex network body ECU) Power management control ECU (power control section) Remote climate control system power ON/OFF request signal CAN Remote climate control system mode notification signal Power management control ECU (HV system control section) HV system ON/OFF request signal Air conditioning amplifier assembly Remote climate control system mode notification signal Certification ECU (smart key ECU assembly) Remote climate control system mode notification signal Telematics Transceiver (DCM) Remote climate control system mode notification signal Power management control ECU (power control section) Main body ECU (multiplex network body ECU) Power mode status signal CAN Power management control ECU (HV system control section) Main body ECU (multiplex network body ECU) Remote climate control system activation permission signal CAN Remote climate control system activation prohibition signal Air conditioning amplifier assembly Remote climate control system activation permission signal Remote climate control system activation prohibition signal Telematics Transceiver (DCM) Remote climate control system activation permission signal Remote climate control system activation prohibition signal Air conditioning amplifier assembly Main body ECU (multiplex network body ECU) Remote climate control system OFF request signal CAN Telematics Transceiver (DCM) Remote climate control system OFF request signal Telematics Transceiver (DCM) Main body ECU (multiplex network body ECU) Remote climate control system ON request signal CAN Air conditioning amplifier assembly Telematics Transceiver (DCM) Cabin temperature level signal CAN IT cooperative control outlet signal HINT: For details of the remote climate control system, refer to System Description. Refer to «SYSTEM DESCRIPTION»(ref-553294-S06349680242013051700000).

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1. GENERAL The air conditioning system uses the following types of control. Control Outline 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 or output relationship that is similar to a human brain. Outlet Air Temperature Control In compliance with the temperature set at the temperature control switch, the neural network control calculates the outlet temperature based on the input signals from various sensors. In addition, corrections in accordance with the signals from the evaporative temperature sensor and water temperature sensor are added to control the outlet air temperature. 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. Air Outlet Control Automatically switches the outlets in accordance with the outlet mode ratio that has been calculated by the neural network control based on the input signals from various sensors. Micro Dust and Pollen Filter Mode Control Activated by the micro dust and pollen filter mode switch operation. Switches the air vent to 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. Air Inlet Control Automatically controls the air inlet control damper in accordance with the outlet temperature that has been calculated by the neural network control. Electric Inverter Compressor Control Compressor Speed Control The air conditioning amplifier assembly calculates the target speed of the compressor based on the target evaporator temperature (which is calculated by the temperature control switch, room temperature sensor, ambient temperature sensor, and 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 temperature control switch, room temperature sensor, ambient temperature sensor, 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. PTC Heater Control When the hybrid control system is operating (READY), and the blower motor is turned on, the air conditioning amplifier assembly turns on the PTC 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). ECO Mode Control When the eco mode switch is turned on, the air conditioning amplifier assembly limits the air conditioning system performance. Remote Climate Control System Control When the remote A/C switch on the key (electrical transmitter) or smart phone (mobile phone terminal) is operated, the air conditioning system is automatically controlled and operated for a maximum of 10 minutes using power from the household power supply or HV battery.
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 sunlight 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 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 Defrosts the windshield through the center defroster, side defrosters and side registers. FOOT/DEF F Defrosts the windshield through the center defroster, side defrosters, side registers while air is also blown out from the front and rear footwell register ducts. FOOT H 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 I, G Air blows out of the center register, side registers and front and rear footwell register ducts. FACE I, E Air blows out of the center register and side registers.
4. AIR OUTLETS AND AIRFLOW VOLUME Air Outlets and Airflow Volume 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. OUTLINE OF REMOTE CLIMATE CONTROL SYSTEM Outline When the remote A/C switch on the key (electrical transmitter) or smart phone (mobile phone terminal) is operated, the air conditioning system is automatically controlled and operated for a maximum of 10 minutes using power from the household power supply or HV battery. HINT: The remote climate control system operates regardless of the plug-in cable connection condition. When the plug-in cable is connected, the remote climate control system is operated using power from the HV battery or household power supply. When the plug-in cable is not connected, the remote climate control system is operated using power only from the HV battery. The remote climate control system starts operating when all of the following operating conditions are met. OPERATING CONDITION Item Condition Power switch condition Off Power switch is not pressed Door lock condition All doors are closed and locked. Hood is closed. Brake pedal condition Not operated (not depressed) Security condition Not in alarm sounding state Shift selection condition Park (P) is selected. Cabin temperature condition Higher than air conditioning temperature set by user Air conditioning is necessary HV battery condition HV battery state or change is sufficient. (Reference value: level 5 or higher) Function of Main Components Each component of the remote climate control system has the functions described in the table. FUNCTION OF MAIN COMPONENTS Component Outline Key (electrical transmitter) Sends remote climate control system on/off signals to the certification ECU. Smart phone (mobile phone terminal) Sends remote climate control system on/off signals to the telematics transceiver (DCM) via the center. Certification ECU (smart key ECU assembly) Receives a signal from the key (electrical transmitter) and sends a signal to the main body ECU (multiplex network body ECU). Telematics Transceiver (DCM) Performs wireless communication with the center. Receives remote climate control system on/off signals from the smart phone (mobile phone terminal) via the center. Remote climate control system on/off signals to the main body ECU (multiplex network body ECU). Main body ECU (multiplex network body ECU) Locks all of the doors. Checks that all of the doors are closed and locked. Checks that the hood is closed. When the remote climate control system starts, the main body ECU (multiplex network body ECU) operates the wireless door lock system. Power management control ECU Turns the vehicle power (12 V) on/off. Starts/stops the HV system. Controls the inverter with converter assembly. Checks if park (P) is selected. Checks the brake pedal condition. Permits/prohibits remote climate control system operation. HV battery Supplies drive power of the remote climate control system. Air conditioning amplifier assembly Judges whether the air conditioning function is operating during remote climate control system operation. Checks the operation of the air conditioning system based on signals from various sensors. Controls the air conditioning system. Judges when to stop the remote climate control system. Inverter with converter assembly Supplies drive power to the compressor with motor assembly. Compressor with motor assembly Compresses refrigerant using power from the household power supply or HV battery.
6. EJECTOR CYCLE SYSTEM In a conventional refrigerant cycle, liquid refrigerant gas is sent into the evaporator using the expansion valve, generating cold air. However, a rapid decrease in the refrigerant pressure forms swirls, causing energy loss. In an ejector cycle, the energy loss caused by the cooler expansion valve is utilized by the operation of the ejector that injects and expands a high-pressure refrigerant, thus improving energy consumption efficiency. The ejector includes nozzle, mixing and diffuser portions. A high temperature and pressure liquid refrigerant flowing from the condenser is introduced into the mixing section through the nozzle at high speeds as the nozzle is inwardly tapered. This decreases the refrigerant pressure in the vicinity of the nozzle, introducing low temperature and pressure gaseous refrigerant into the nozzle from the evaporator. Thus, both refrigerants are mixed in the mixing section and are introduced into the diffuser section. As the diffuser section is outwardly flared, the refrigerant flow rate in the diffuser decreases and the refrigerant pressure rises. Through these operations, the refrigerant pressure in the evaporator on the downwind side can be constantly kept lower than that on the upwind side, creating lower temperature conditions. Therefore, air cooled by the evaporator on the upwind side can be further cooled by that on the downwind side, thus improving the efficiency of the evaporator.
7. MICRO DUST AND POLLEN FILTER MODE CONTROL When the micro dust and pollen filter mode switch is pressed, the micro dust and pollen filter mode control is activated. Then, the air vent is switched to 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 mode switch signal is input to the air conditioning amplifier assembly, the air conditioning amplifier assembly controls the compressor with motor assembly, air inlet control servo motor, air outlet control 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 (5°C (41°F) maximum), 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.
8. 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. 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/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 power consumption. PTC Heater Control Stops the operation of the PTC heater assembly and suppresses 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 power consumption.
9. COMPRESSOR WITH MOTOR ASSEMBLY Compressor Control 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 ND-OIL 11 compressor oil with a high level of insulation performance. Therefore, never use compressor oil other than the ND-OIL 11 type compressor oil or its equivalent. 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 with motor assembly 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 temperature control switch, room temperature sensor, ambient temperature sensor, automatic light control sensor, and evaporator temperature sensor. Accordingly, the air conditioning amplifier assembly controls the compressor speed to an extent that does not inhibit proper cooling performance or defogging performance. The compressor with motor assembly uses high-voltage alternating current. If a short or open circuit occurs in the compressor with motor assembly 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.
10. PTC HEATER 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. 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, engine speed, temperature setting, and electrical load (generator power ratio).
11. BLOWER MOTOR 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.
12. BUS CONNECTOR (AIR CONDITIONING HARNESS ASSEMBLY) A bus connector is used in the wire harness connection 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.
13. 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.
14. 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 assembly.
15. ROOM TEMPERATURE 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 assembly.
16. 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 assembly.
17. SOLAR SENSOR (AUTOMATIC LIGHT CONTROL SENSOR) The solar sensor (automatic light control sensor) detects changes in the amount of sunlight and outputs it to the air conditioning amplifier assembly in the form of voltage changes.
18. 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
• REMOVAL