Home/Toyota/Prius C/Toyota Prius C I facelift (2014-2014)/Repair manual/Automatic HVAC System/Air Conditioning System (Diagnostic Codes & Circuit Tests):…
Contents Wiring diagrams Section: Automatic HVAC System All sections

Air Conditioning System (Diagnostic Codes & Circuit Tests): Overview Toyota Prius C I facelift

Automatic HVAC System 19 illustrations ~1717 words

DESCRIPTION

The room temperature sensor (cooler thermistor) is installed in the instrument panel to detect the cabin temperature which is used to control heater and air conditioning system AUTO mode. The resistance of the room temperature sensor (cooler thermistor) changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies a voltage (5 V) to the room temperature sensor (cooler thermistor) and reads voltage changes due to changes in the resistance of the room temperature sensor (cooler thermistor).

DTC No.DTC Detection ConditionTrouble Area
B1411/11Open or short in room temperature sensor (cooler thermistor) circuitRoom temperature sensor (cooler thermistor) Harness or connector between room temperature sensor (cooler thermistor) and air conditioning amplifier assembly Air conditioning amplifier assembly

Scheme 98

Scheme 98: WIRING DIAGRAM

The ambient temperature sensor (thermistor assembly) is installed in front of the condenser to detect the ambient temperature. Its signal is used for air conditioning control in AUTO mode. This sensor is connected to the air conditioning amplifier assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the air conditioning amplifier assembly. The resistance of the ambient temperature sensor (thermistor assembly) changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies a voltage (5 V) to the ambient temperature sensor (thermistor assembly) and reads voltage changes due to changes in the resistance of the ambient temperature sensor (thermistor assembly).

DTC No.DTC Detection ConditionTrouble Area
B1412/12Open or short in ambient temperature sensor (thermistor assembly) circuitAmbient temperature sensor (thermistor assembly) Harness or connector between ambient temperature sensor (thermistor assembly) and air conditioning amplifier assembly Air conditioning amplifier assembly

Scheme 99

Scheme 99: WIRING DIAGRAM

The evaporator temperature sensor (No. 1 cooler thermistor) is installed on the evaporator in the air conditioner unit to detect the temperature of the air that has passed through the evaporator. Its signal is used for air conditioning control. It sends signals to the air conditioning amplifier assembly. The resistance of the evaporator temperature sensor (No. 1 cooler thermistor) changes in accordance with the cooled air temperature that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies voltage (5 V) to the evaporator temperature sensor (No. 1 cooler thermistor) and reads voltage changes as the resistance of the evaporator temperature sensor (No. 1 cooler thermistor) changes. This sensor is used for frost prevention.

DTC No.DTC Detection ConditionTrouble Area
B1413/13Open or short in evaporator temperature sensor (No. 1 cooler thermistor) circuitEvaporator temperature sensor (No. 1 cooler thermistor) Air conditioning harness assembly Air conditioning amplifier assembly

Scheme 100

Scheme 100: WIRING DIAGRAM

This DTC is stored if refrigerant pressure on the high pressure side is extremely low (190 kPa (1.9 kgf/cm 2 , 28 psi) or less) or extremely high (3140 kPa (32.0 kgf/cm 2 , 455 psi) or more). The air conditioning pressure sensor, which is installed on the pipe on the high pressure side to detect refrigerant pressure, sends a refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts this signal to a pressure value according to the sensor characteristics and uses it to control the compressor.

DTC No.DTC Detection ConditionTrouble Area
B1423/23Open or short in air conditioning pressure sensor circuit Refrigerant pressure on the high pressure side is extremely low (190 kPa (1.9 kgf/cm 2 , 28 psi) or less) or extremely high (3140 kPa (32.0 kgf/cm 2 , 455 psi) or more).Air conditioning pressure sensor Harness or connector between air conditioning pressure sensor and air conditioning amplifier assembly Air conditioning amplifier assembly Cooler expansion valve (blocked, stuck) Cooler dryer (moisture in the refrigerant cycle cannot be absorbed) Condenser assembly (blocked, deterioration of cooling capacity due to dirt) Cooling fan system (condenser assembly cannot be cooled down) A/C system (leaks, blocked)

Scheme 101

Scheme 101: WIRING DIAGRAM

The No. 1 air conditioning radiator damper servo sub-assembly (air mix) sends pulse signals to indicate the damper position to the air conditioning amplifier assembly. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the No. 1 air conditioning radiator damper servo sub-assembly (air mix) to the appropriate position. This adjusts the amount of air passing through the heater core after passing the evaporator and controls the temperature of the output air.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

HINT

Confirm that no mechanical problem is present because this diagnostic code can be stored when either a damper link or the damper is mechanically locked.

DTC No.DTC Detection ConditionTrouble Area
B1441/41Air mix damper position sensor value does not change even though air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (air mix).No. 1 air conditioning radiator damper servo sub-assembly (air mix) Air conditioning harness assembly Air conditioning amplifier assembly

Scheme 102

Scheme 102: WIRING DIAGRAM

The No. 1 blower damper servo sub-assembly (air inlet) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal, reverse) based on the signals to move the air inlet mode selection No. 1 blower damper servo sub-assembly (air inlet) to any position, which controls the intake air settings (FRESH, FRESH/RECIRCULATION, and RECIRCULATION).

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

HINT

Confirm that no mechanical problem is present because this diagnostic code can be stored when either a damper link or the damper is mechanically locked.

DTC No.DTC Detection ConditionTrouble Area
B1442/42Air inlet damper position sensor value does not change even though air conditioning amplifier assembly operates No. 1 blower damper servo sub-assembly (air inlet).No. 1 blower damper servo sub-assembly (air inlet) Air conditioning harness assembly Air conditioning amplifier assembly

Scheme 103

Scheme 103: WIRING DIAGRAM

The No. 2 air conditioning radiator damper servo sub-assembly (air outlet) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal, reverse) based on the signals to move the No. 2 air conditioning radiator damper servo sub-assembly (air outlet) to any position, which controls the air outlet switching.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

HINT

Confirm that no mechanical problem is present because this diagnostic code can be stored when either a damper link or the damper is mechanically locked.

DTC No.DTC Detection ConditionTrouble Area
B1443/43Air outlet damper position sensor value does not change even though the air conditioning amplifier assembly operates the No. 2 air conditioning radiator damper servo sub-assembly (air outlet).No. 2 air conditioning radiator damper servo sub-assembly (air outlet) Air conditioning harness assembly Air conditioning amplifier assembly

Scheme 104

Scheme 104: WIRING DIAGRAM

The A/C inverter assembly monitors the voltage of the HV battery. It stops compressor control and stores the DTC when the monitored voltage is outside the specified range.

The DTC will be stored as a history DTC. Compressor control may not resume unless the ignition switch is turned off.

DTC No.DTC Detection ConditionTrouble Area
B1471/71Open or short in A/C inverter high voltage power resource system The boost inverter is broken or malfunctioningElectric vehicle fuse No. 2 engine wire (harness or connector between compressor with motor assembly and inverter with converter assembly) Compressor with motor assembly Hybrid control system CAN communication system

Scheme 105

Scheme 105: WIRING DIAGRAM

The inverter in the compressor with motor assembly outputs high-voltage to operate the motor. If there is an open or short in the output circuit, the ECU will stop compressor operation and store the DTC. The DTC will be stored as a history DTC. The compressor operation remains stopped until both the history and current DTCs are cleared.

DTC No.DTC Detection ConditionTrouble Area
B1472/72Open or short in A/C inverter high voltage output systemCompressor with motor assembly CAN communication system

The inverter activation signal is sent to the compressor with motor assembly from the power management control ECU. Compressor control is stopped and the DTC is stored if there is an open or short in the signal circuit.

DTC No.DTC Detection ConditionTrouble Area
B1473/73Open or short in A/C inverter start-up signal systemHarness or connector between power management control ECU and compressor with motor assembly Compressor with motor assembly Power management control ECU Hybrid control system CAN communication system

Scheme 106

Scheme 106: WIRING DIAGRAM
DTC No.DTC Detecting ConditionTrouble Area
B1474/74A/C inverter malfunctionCompressor with motor assembly CAN communication system

The temperature sensor of the compressor with motor assembly detects its inverter temperature.

If the temperature exceeds the maximum, the operation of the compressor with motor assembly will be stopped, and this DTC will be stored.

DTC No.DTC Detection ConditionTrouble Area
B1475/75Temperature of the inverter is outside the specified range (temperature is too high), or there is an open or short to ground in the temperature sensor circuit.Cooling fan system Refrigerant volume Compressor with motor assembly CAN communication system

The operation of the compressor with motor assembly is stopped and a DTC is stored if the rotation load is too large or too small while the compressor with motor assembly is operating.

Possible causes are refrigerant leaks, overcharged refrigerant, insufficient cooling because of a condenser fan circuit malfunction, or compressor lock.

DTC No.DTC Detection ConditionTrouble Area
B1476/76Motor rotation load while the compressor is operating is too large or too smallRefrigerant volume Compressor with motor assembly Cooling fan system CAN communication system

The compressor with motor assembly monitors the control power voltage in the circuit. It stops the compressor circuit and stores the DTC when the monitored voltage is outside the specified range.

The DTC will be stored as a history DTC. Compressor control may not resume unless the ignition switch is turned off.

DTC No.DTC Detection ConditionTrouble Area
B1477/77An open or short to ground in the inverter control power voltage circuitCompressor with motor assembly CAN communication system

The air conditioning harness assembly connects the air conditioning amplifier assembly and the servo motors. The air conditioning amplifier assembly supplies power and sends operation instructions to each servo motor through the air conditioning harness assembly. Each servo motor sends damper position information to the air conditioning amplifier assembly.

DTC No.DTC Detection ConditionTrouble Area
B1497/97Error or open in communication lineAir conditioning harness assembly No. 1 air conditioning radiator damper servo sub-assembly No. 2 air conditioning radiator damper servo sub-assembly No. 1 blower damper servo sub-assembly Air conditioning amplifier assembly

Scheme 107

Scheme 107: WIRING DIAGRAM

The power management control ECU and compressor with motor assembly transmit information to one another via a communication line. Compressor control is stopped and the DTC is stored if communication information is cut off or abnormal information occurs.

The DTC is also detected if high-voltage power supplied from the inverter with converter assembly to the compressor control circuit is shut off.

The DTC will be stored as a history DTC.

DTC No.DTC Detection ConditionTrouble Area
B1498/98Communication line error or open between the power management control ECU and compressor with motor assembly. High-voltage power source is shut off.Harness or connector between power management control ECU, compressor with motor assembly and body ground Power management control ECU Compressor with motor assembly No. 2 engine wire (harness or connector between compressor with motor assembly and inverter with converter assembly) Electric vehicle fuse CAN communication system Hybrid control system

Scheme 108

Scheme 108: WIRING DIAGRAM

The air conditioning panel (heater control switch board) communicates with the air conditioning amplifier assembly through the LIN communication system.

If the LIN communication system malfunctions, the air conditioning amplifier assembly does not operate even if the air conditioning panel (heater control switch board) is operated.

DTC No.DTC Detection ConditionTrouble Area
B14B2Lost communication with the air conditioning panel (heater control switch board).Harness or connector between air conditioning panel (heater control switch board) and IG circuit Harness or connector between air conditioning panel (heater control switch board) and body ground LIN communication system Air conditioning panel (heater control switch board) Air conditioning amplifier assembly

Scheme 109

Scheme 109: WIRING DIAGRAM

SYSTEM DESCRIPTION

This DTC is stored if the amount of refrigerant in the air conditioning system is insufficient.

The air conditioning amplifier assembly receives the ambient temperature signal, refrigerant pressure signal etc. from various sensors.

Based on these signals, the air conditioning amplifier assembly detects the amount of refrigerant.

The A/C switch indicator is turned off and air conditioning system is stopped if the amount of refrigerant is insufficient.

DTC No.DTC Detection ConditionTrouble Area
B14B8When the following conditions is detected using the refrigerant shortage check in normal operation: The amount of refrigerant is insufficient.Refrigerant pipe line Cooler expansion valve Air conditioning amplifier assembly

This DTC is stored if there is insulation trouble with the high-voltage circuit in the air conditioning system. Possible causes are poor insulation in the compressor with motor assembly, or mixing of any oil other than ND-OIL 11 in the refrigerant cycle.

A high-voltage motor is built into the electrical compressor and is cooled directly with refrigerant. Compressor oil (ND-OIL 11) with high insulation performance is used because a leakage of electrical power may occur if regular compressor oil (ND-OIL 8) is used.

WARNINGWear insulated gloves and pull out the service plug grip before inspection as procedures may require disconnecting high-voltage connectors. Carry the removed service plug in your pocket to prevent other technicians from accidentally reconnecting it while you are servicing the vehicle. Do not touch the high-voltage connectors or terminals for 10 minutes after the service plug grip is removed.
DTC No.DTC Detection ConditionTrouble Area
P0AA6-611High voltage system insulation malfunctionCompressor oil Refrigerant pipe line Compressor with motor assembly CAN communication system

Scheme 110

Scheme 110: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0101No communication with TCMCAN communication system Power management control ECU
U0142No communication with main body ECUCAN communication system Main body ECU (multiplex network body ECU)
U0155No communication with combination meterCAN communication system Combination meter assembly
U0293No communication with HV ECUCAN communication system Power management control ECU

The blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.

Scheme 111

Scheme 111: WIRING DIAGRAM

The air conditioning amplifier assembly sends operation signals to the PTC HTR relays when quick heater assembly (PTC heater) operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC HTR relays turn on, and power is supplied to the quick heater assembly (PTC heater) installed in the air conditioning radiator assembly.

Control ECUCondition
Air Conditioning Amplifier AssemblyBlower motor on
Temperature set to MAX HOT
ECO mode switch (eco switch assembly) off
IDH terminal signal less than 1 V (Inverter with converter assembly overload not detected)
Engine coolant temperature approximately 50°C or lower
Ambient temperature 10°C or lower

QUICK HEATER ASSEMBLY (PTC HEATER) OPERATION CONDITION

Scheme 112

Scheme 112: WIRING DIAGRAM

The temperature can be adjusted and the air inlet can be switched between fresh air mode and recirculated mode by operating switches on the steering pad switch RH. The air conditioning panel (heater control switch board) receives operation signals from the steering pad switch RH via the spiral with sensor cable sub-assembly and sends temperature setting and air inlet change signals to the air conditioning amplifier assembly.

Scheme 113

Scheme 113: WIRING DIAGRAM

When the ECO mode switch (eco switch assembly) is turned on, the air conditioning amplifier assembly receives an ECO mode switch (eco switch assembly) on signal and controls the air conditioning to enhance fuel efficiency.

Scheme 114

Scheme 114: WIRING DIAGRAM

Power is supplied to the air conditioning amplifier assembly when the ignition switch is ON (IG).

The power is used for operating the air conditioning amplifier assembly, servo motors, etc.

Scheme 115

Scheme 115: WIRING DIAGRAM

The back-up power source circuit for the air conditioning amplifier assembly is shown below. Power is supplied even when the ignition switch is off. The power is used for diagnostic trouble code memory, etc.

Scheme 116

Scheme 116: WIRING DIAGRAM