Air Conditioning System (Diagnostic Codes & Circuit Tests): Overview Scion tC II рестайлинг

DESCRIPTION

The thermistor assembly is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner. The thermistor assembly is connected to the combination meter assembly and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The thermistor assembly sends a signal to the air conditioning amplifier assembly via the combination meter assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The combination meter assembly applies a voltage (5 V) to the thermistor assembly and reads voltage changes as changes in the resistance of the thermistor assembly. The combination meter assembly sends the read signal to the air conditioning amplifier assembly via CAN communication.

Scheme 140

The thermistor assembly is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner. The thermistor assembly is connected to the combination meter assembly and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The thermistor assembly sends a signal to the air conditioning amplifier assembly via the combination meter assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The combination meter assembly applies a voltage (5 V) to the thermistor assembly and reads voltage changes as changes in the resistance of the thermistor assembly. The combination meter assembly sends the read signal to the air conditioning amplifier assembly via CAN communication.

The No. 1 cooler thermistor is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air that has passed through the No. 1 cooler evaporator sub-assembly and control the air conditioning. It sends appropriate signals to the air conditioning amplifier assembly. The resistance of the No. 1 cooler thermistor changes in accordance with the temperature of the cooled air that has passed through the No. 1 cooler evaporator sub-assembly. 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 No. 1 cooler thermistor and reads voltage changes as the resistance of the No. 1 cooler thermistor changes. The No. 1 cooler thermistor is used for frost prevention.

Scheme 141

Scheme 142

1. READ VALUE USING TECHSTREAM (EVAPORATOR FIN THERMISTOR) Use the Data List to check if the No. 1 cooler thermistor is functioning properly. Refer to «DATA LIST / ACTIVE TEST [05/2013 - ]»(ref-615247-S31232994112014050900000). AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Evaporator Fin Thermistor No. 1 cooler thermistor / Min.: -29.7°C (-21.46°F) Max.: 59.55°C (139.19°F) Actual evaporator temperature displayed Open in the circuit: -29.7°C (-21.46°F). Short in the circuit: 59.55°C (139.19°F). OK The display is as specified in the normal condition column. RESULT Result Proceed to OK (When troubleshooting according to problem symptoms table) A OK (When troubleshooting according to DTC) B NG C B --> See step 5 C --> See step 2 A --> See step 6
2. INSPECT NO. 1 COOLER THERMISTOR Remove the No. 1 cooler thermistor. Refer to «REMOVAL [05/2013 - 01/2014]»(ref-615270-S16141938682014050900000). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 1 (+) - 2 (-) -10°C (14°F) 7.30 to 9.10 kohms -5°C (23°F) 5.65 to 6.95 kohms 0°C (32°F) 4.40 to 5.35 kohms 5°C (41°F) 3.40 to 4.15 kohms 10°C (50°F) 2.70 to 3.25 kohms 15°C (59°F) 2.14 to 2.58 kohms 20°C (68°F) 1.71 to 2.05 kohms 25°C (77°F) 1.38 to 1.64 kohms 30°C (86°F) 1.11 to 1.32 kohms TEXT IN ILLUSTRATION *a Sensing Portion *b Resistance *c Allowable Range *d Temperature NOTE: Even slightly touching the No. 1 cooler thermistor may change the resistance value. Be sure to hold the connector of the No. 1 cooler thermistor. When measuring, the No. 1 cooler thermistor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (refer to the graph). NG --> See step 4 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (NO. 1 COOLER THERMISTOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) Disconnect the C28 thermistor connector. Disconnect the C32 amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition C32-22 (TE) - C28-1 (+) Always Below 1 ohms C32-23 (SG-3) - C28-2 (-) Always Below 1 ohms C32-22 (TE) - Body ground Always 10 kohms or higher C32-23 (SG-3) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. REPLACE NO. 1 COOLER THERMISTOR. Refer to «REMOVAL [05/2013 - 01/2014]»(ref-615270-S16141938682014050900000)
5. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL [05/2013 - ]»(ref-615270-S32704544182014050900000)
6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE [05/2013 - 01/2014]»(ref-615247-S35623382742014050900000)

The No. 1 cooler thermistor is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air that has passed through the No. 1 cooler evaporator sub-assembly and control the air conditioning. It sends appropriate signals to the air conditioning amplifier assembly. The resistance of the No. 1 cooler thermistor changes in accordance with the temperature of the cooled air that has passed through the No. 1 cooler evaporator sub-assembly. 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 No. 1 cooler thermistor and reads voltage changes as the resistance of the No. 1 cooler thermistor changes. The No. 1 cooler thermistor is used for frost prevention.

This DTC is stored when the refrigerant pressure is extremely low (177 kPa [1.8 kgf/cm 2 , 26 psi] or less) or extremely high (3030 kPa [30.9 kgf/cm 2 , 439 psi] or higher). The air conditioner pressure sensor, which is installed on the pipe of the high pressure side to detect the refrigerant pressure, outputs the refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts the signal to a pressure value according to the sensor characteristics to control the compressor.

HINT

Be sure to check the refrigerant volume first when this DTC is output because this DTC may also be stored if there is no refrigerant in the cycle.

Scheme 143

This DTC is stored when the refrigerant pressure is extremely low (177 kPa [1.8 kgf/cm 2 , 26 psi] or less) or extremely high (3030 kPa [30.9 kgf/cm 2 , 439 psi] or higher). The air conditioner pressure sensor, which is installed on the pipe of the high pressure side to detect the refrigerant pressure, outputs the refrigerant pressure signal to the air conditioning amplifier assembly. The air conditioning amplifier assembly converts the signal to a pressure value according to the sensor characteristics to control the compressor.

HINT

Be sure to check the refrigerant volume first when this DTC is output because this DTC may also be stored if there is no refrigerant in the cycle.

In this circuit, the compressor assembly with pulley receives a refrigerant compression demand signal from the air conditioning amplifier assembly.

Based on this signal, the compressor changes the amount of compressor output.

Scheme 144

In this circuit, the compressor assembly with pulley receives a refrigerant compression demand signal from the air conditioning amplifier assembly.

Based on this signal, the compressor changes the amount of compressor output.

The flow sensor is built into the compressor assembly with pulley, and outputs a signal indicating the flow rate of the refrigerant. The air conditioning amplifier assembly converts the received signal to refrigerant flow rate data according to the characteristics of the sensor, which it then sends to the ECM via CAN communication.

Scheme 145

The flow sensor is built into the compressor assembly with pulley, and outputs a signal indicating the flow rate of the refrigerant. The air conditioning amplifier assembly converts the received signal to refrigerant flow rate data according to the characteristics of the sensor, which it then sends to the ECM via CAN communication.

The air conditioning amplifier communicates with the ECM, main body ECU (multiplex network body ECU) and combination meter assembly through the CAN communication system.

The air conditioning amplifier communicates with the ECM, main body ECU (multiplex network body ECU) and combination meter assembly through the CAN communication system.

The recirculation damper servo sub-assembly and No. 1 heater control sub-assembly are powered through the HTR-IG fuse. Operating the No. 1 heater control sub-assembly drives the recirculation damper servo sub-assembly to switch between "Fresh" and "Recirculation".

Scheme 146

The recirculation damper servo sub-assembly and No. 1 heater control sub-assembly are powered through the HTR-IG fuse. Operating the No. 1 heater control sub-assembly drives the recirculation damper servo sub-assembly to switch between "Fresh" and "Recirculation".

When the blower switch is set to position 1 or higher, the contact of the heater blower motor relay assembly is closed, current flows to the blower with fan motor sub-assembly, and the blower with fan motor sub-assembly operates. Operating the No. 2 heater control sub-assembly changes how the current flows to the motor through the resistors of the blower resistor, thereby changing the motor speed.

Scheme 147

When the blower switch is set to position 1 or higher, the contact of the heater blower motor relay assembly is closed, current flows to the blower with fan motor sub-assembly, and the blower with fan motor sub-assembly operates. Operating the No. 2 heater control sub-assembly changes how the current flows to the motor through the resistors of the blower resistor, thereby changing the motor speed.

The No. 3 heater control sub-assembly is powered through the HTR-IG fuse. The No. 3 heater control sub-assembly transmits operation signals of each switch to the air conditioning amplifier assembly.

Scheme 148

The No. 3 heater control sub-assembly is powered through the HTR-IG fuse. The No. 3 heater control sub-assembly transmits operation signals of each switch to the air conditioning amplifier assembly.

The main power source is supplied to the air conditioning amplifier assembly when the ignition switch is turned to ON. The power source is used for operating the air conditioning amplifier assembly, recirculation damper servo motor sub-assembly, etc.

Scheme 149

The main power source is supplied to the air conditioning amplifier assembly when the ignition switch is turned to ON. The power source is used for operating the air conditioning amplifier assembly, recirculation damper servo motor sub-assembly, etc.

See also:
• ON-VEHICLE INSPECTION [05/2013 - ]