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

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 141

Scheme 142

1. CHECK CAN COMMUNICATION SYSTEM Use the Techstream to check if the CAN communication system is functioning normally. Refer to «DIAGNOSIS SYSTEM»(ref-451206-S32661733752012020700000). OK CAN DTC is not output. NG --> See step 11 OK: Go to next step
2. READ VALUE USING TECHSTREAM (AMBIENT TEMP SENSOR) Use the Data List to check if the thermistor assembly is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-451181-S37068168782012020700000). AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sensor Thermistor assembly / Min: -23.3°C (-9.94°F) Max: 65.95°C (150.71°F) Actual ambient temperature displayed Open in the circuit: -23.3°C (-9.94°F). Short in the circuit: 65.95°C (150.71°F). The combination meter assembly sends the ambient temperature signal to the air conditioning amplifier assembly via CAN communication. 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 8 C --> See step 3 A --> See step 10
3. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE) Use the Data List to check if the thermistor assembly is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-451181-S37068168782012020700000). COMBINATION METER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temperature Ambient temperature / Min: -40.0°C (-40.0°F) Max: 87.5°C (189.5°F) Actual ambient temperature displayed Open in the circuit: -40.0°C (-40.0°F). Short in the circuit: 87.5°C (189.5°F). OK The display is as specified in the normal condition column. NG --> See step 6 OK: Go to next step
4. REPLACE COMBINATION METER ASSEMBLY Temporarily replace the combination meter assembly with a new or normally functioning one. Refer to «REMOVAL»(ref-451189-S19812075632012020700000). NEXT: Go to next step
5. CHECK FOR DTC Clear the DTCs. Refer to «DTC CHECK / CLEAR»(ref-451181-S15098254282012020700000). Check the DTCs. Refer to «DTC CHECK / CLEAR»(ref-451181-S15098254282012020700000). OK DTC B1412 is not output. NG --> See step 8 OK --> END (COMBINATION METER ASSEMBLY IS FAULTY)
6. INSPECT THERMISTOR ASSEMBLY Remove the thermistor assembly. Refer to «REMOVAL»(ref-451191-S36300711242012020700000). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 1 - 2 10°C (50°F) 3.00 to 3.73 kohms 15°C (59°F) 2.45 to 2.88 kohms 20°C (68°F) 1.95 to 2.30 kohms 25°C (77°F) 1.60 to 1.80 kohms 30°C (86°F) 1.28 to 1.47 kohms 35°C (95°F) 1.00 to 1.22 kohms 40°C (104°F) 0.80 to 1.00 kohms 45°C (113°F) 0.65 to 0.85 kohms 50°C (122°F) 0.50 to 0.70 kohms 55°C (131°F) 0.44 to 0.60 kohms 60°C (140°F) 0.36 to 0.50 kohms TEXT IN ILLUSTRATION *a Sensing Portion *b Resistance *c Allowable Range *d Temperature NOTE: Even slightly touching the thermistor assembly may change the resistance value. Be sure to hold the connector of the thermistor assembly. When measuring, the thermistor assembly temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (refer to the graph). NG --> See step 9 OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY - COMBINATION METER ASSEMBLY) Disconnect the A18 thermistor connector. Disconnect the C50 meter connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A18-1 - C50-13 (TEMP) Always Below 1 ohms A18-2 - C50-12 (TX1+) Always Below 1 ohms C50-13 (TEMP) - Body ground Always 10 kohms or higher C50-12 (TX1+) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 12
8. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-451191-S05937696272012020700000)
9. REPLACE THERMISTOR ASSEMBLY. Refer to «REMOVAL»(ref-451191-S36300711242012020700000)
10. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-451181-S34414911302012020700000)
11. GO TO CAN COMMUNICATION SYSTEM. Refer to «DIAGNOSIS SYSTEM»(ref-451206-S32661733752012020700000)
12. REPLACE COMBINATION METER ASSEMBLY. Refer to «REMOVAL»(ref-451189-S19812075632012020700000)

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 143

Scheme 144

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»(ref-451181-S37068168782012020700000). 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 4 C --> See step 2 A --> See step 6
2. INSPECT NO. 1 COOLER THERMISTOR Remove the No. 1 cooler thermistor. Refer to «REMOVAL»(ref-451191-S34455536942012020700000). 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 5 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 4
4. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-451191-S05937696272012020700000)
5. REPLACE NO. 1 COOLER THERMISTOR. Refer to «REMOVAL»(ref-451191-S34455536942012020700000)
6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-451181-S34414911302012020700000)

This DTC is stored when the refrigerant pressure is extremely low (0.176 MPa [1.8 kgf/cm 2 , 25.5 psi] or less) or extremely high (3.025 MPa [30.9 kgf/cm 2 , 438.6 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 145

Scheme 146

Scheme 147

Scheme 148

1. CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - BATTERY) Disconnect the A12 sensor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A12-3 (+) - A12-1 (-) Ignition switch ON 4.75 to 5.25 V Ignition switch off Below 1 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A12-1 (-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Air Conditioner Pressure Sensor) NG --> See step 4 OK: Go to next step
2. CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Remove the air conditioning amplifier assembly with its connectors still connected. Refer to «REMOVAL»(ref-451191-S05937696272012020700000). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition C32-12 (PRE) - Body ground Ignition switch ON A/C switch off 0.63 to 4.72 V TEXT IN ILLUSTRATION *a Component with harness connected (Air Conditioning Amplifier Assembly) HINT: If the measured voltage is not within the normal range, there may be a malfunction in the air conditioning amplifier assembly, air conditioner pressure sensor or wire harness. It is also possible that the amount of refrigerant may not be appropriate. NG --> See step 5 OK: Go to next step
3. CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Remove the air conditioning amplifier assembly with its connectors still connected. Refer to «REMOVAL»(ref-451191-S05937696272012020700000). Measure the voltage when the following conditions are met. MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting Max cold Blower Speed Hi A/C Switch On Air Inlet Control Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If the refrigerant pressure on the high pressure side becomes extremely high during the inspection (the voltage exceeds 4.8 V), the fail-safe function stops the compressor operation. Therefore, measure the voltage before the fail-safe operation. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the problem symptom may recur after a while. HINT: When the outside air temperature is low (below -1.5°C [29.3°F]), the compressor stops due to the operation of the thermistor assembly and No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition C32-12 (PRE) - Body ground Conditions in "Measurement Condition" chart above are met 0.63 to 4.72 V TEXT IN ILLUSTRATION *a Component with harness connected (Air Conditioning Amplifier Assembly) 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 17 C --> See step 11 A --> See step 22
4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) Disconnect the A12 sensor 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 A12-1 (-) - C32-10 (SG-2) Always Below 1 ohms A12-3 (+) - C32-7 (S5-3) Always Below 1 ohms C32-10 (SG-2) - Body ground Always 10 kohms or higher C32-7 (S5-3) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 17
5. CHECK HARNESS AND CONNECTOR (AIR CONDITIONER PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) Disconnect the A12 sensor 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 A12-2 (PR) - C32-12 (PRE) Always Below 1 ohms C32-12 (PRE) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. CHECK FOR AIR CONDITIONING SYSTEM LEAK Install a manifold gauge set. Recover the refrigerant from the air conditioning system using a refrigerant recovery unit. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). Evacuate the air conditioning system and check that vacuum can be maintained in it. OK Vacuum can be maintained in the air conditioning system. HINT: If vacuum cannot be maintained in the air conditioning system, refrigerant may be leaking from it. In this case, it is necessary to repair or replace the leaking part of the air conditioning system. NG --> See step 10 OK: Go to next step
7. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). NEXT: Go to next step
8. CHECK FOR DTC Check for DTCs when the following conditions are met. Refer to «DTC CHECK / CLEAR»(ref-451181-S15098254282012020700000). MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting Max cold Blower Speed Hi A/C Switch On Air Inlet Control Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If the refrigerant pressure on the high pressure side becomes high, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while. HINT: When the outside air temperature is low (below -1.5°C [29.3°F]), the compressor stops due to the operation of the thermistor assembly and No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. OK DTC B1423 is not output. NOTE: If the DTC was stored due to an insufficient or excessive amount of refrigerant, the problem may have been solved after performing the previous step. However, the root cause of insufficient refrigerant may be refrigerant leakage. Therefore, identify and repair the area where refrigerant leaks as necessary. The root cause of excessive refrigerant may be adding too much refrigerant. NG --> See step 9 OK --> END (AMOUNT OF REFRIGERANT IS INCORRECT)
9. CHECK AIR CONDITIONER PRESSURE SENSOR Remove the air conditioning amplifier assembly with its connectors still connected. Refer to «REMOVAL»(ref-451191-S05937696272012020700000). Install a manifold gauge set. Turn the ignition switch to ON. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition C32-12 (PRE) - C32-10 (SG-2) Engine running Refrigerant pressure normal (below 3.025 MPa [30.9 kgf/cm 2, 438.6 psi] and higher than 0.176 MPa [1.8 kgf/cm 2, 25.5 psi]) 0.63 to 4.72 V Engine running Refrigerant pressure abnormal (below 0.176 MPa [1.8 kgf/cm 2, 25.5 psi]) Below 0.63 V Engine running Refrigerant pressure abnormal (higher than 3.025 MPa [30.9 kgf/cm 2, 438.6 psi]) 4.72 V or higher TEXT IN ILLUSTRATION *a Component with harness connected (Air Conditioning Amplifier Assembly) NG --> See step 18 OK --> See step 17
10. REPAIR AIR CONDITIONING SYSTEM LEAK Identify the area where refrigerant leaks. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). Repair the identified area of the air conditioning system. Evacuate the air conditioning system. NEXT --> See step 19
11. CHECK COOLING FAN SYSTEM Check if the cooling fan system is functioning properly. Refer to «ON-VEHICLE INSPECTION»(/scion/tc/ii-2010-2013/remont/cooling-fan/#engine-cooling-fan-system-inspection__on-vehicle-inspection) . OK Cooling fan system is functioning properly. NG --> See step 23 OK: Go to next step
12. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). Evacuate the air conditioning system. Add an appropriate amount of refrigerant. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). HINT: If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and then check for DTCs. NEXT: Go to next step
13. CHECK FOR DTC Check for DTCs when the following conditions are met. Refer to «DTC CHECK / CLEAR»(ref-451181-S15098254282012020700000). MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting Max cold Blower Speed Hi A/C Switch On Air Inlet Control Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If the refrigerant pressure on the high pressure side becomes high, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while. HINT: When the outside air temperature is low (below -1.5°C [29.3°F]), the compressor stops due to the operation of the thermistor assembly and No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant and check for DTCs. If the DTC is not output after this procedure, it indicates that the cooler dryer in the condenser assembly with receiver is not able to absorb moisture in the refrigerant cycle. In this case, to complete the repair, it is necessary to replace the cooler dryer. OK DTC B1423 is not output. NG --> See step 14 OK --> See step 20
14. REPLACE COOLER EXPANSION VALVE Temporarily replace the cooler expansion valve with a new or normally functioning one. Refer to «REMOVAL»(ref-451191-S39978217202012020700000). HINT: Replace the cooler expansion valve with a new or normally functioning one because the cooler expansion valve is either stuck or clogged. NEXT: Go to next step
15. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000). NEXT: Go to next step
16. CHECK FOR DTC Check for DTCs when the following conditions are met. Refer to «DTC CHECK / CLEAR»(ref-451181-S15098254282012020700000). MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting Max cold Blower Speed Hi A/C Switch On Air Inlet Control Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If the refrigerant pressure on the high pressure side becomes high, a DTC will be stored. Therefore, it is necessary to check for DTCs after a certain amount of time (approximately 10 minutes) has passed because the DTC may be stored after the air conditioning system operates for a while. HINT: When the outside air temperature is low (below -1.5°C [29.3°F]), the compressor stops due to the operation of the thermistor assembly and No. 1 cooler thermistor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If the refrigerant pressure is not normal after replacing the expansion valve with a new or normally functioning one, the cooler condenser assembly or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the condenser assembly with receiver or the pipes. OK DTC B1423 is not output. NG --> See step 21 OK --> END (COOLER EXPANSION VALVE IS FAULTY)
17. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-451191-S05937696272012020700000)
18. REPLACE AIR CONDITIONER PRESSURE SENSOR. Refer to «REMOVAL»(ref-451191-S07705009212012020700000)
19. CHARGE REFRIGERANT. Refer to «REPLACEMENT»(ref-451191-S17073672162012020700000)
20. REPLACE COOLER DRYER. Refer to «REMOVAL»(ref-451191-S11121611642012020700000)
21. CLEAN OR REPLACE CONDENSER ASSEMBLY WITH RECEIVER OR PIPES. Refer to «REMOVAL»(ref-451191-S11121611642012020700000)
22. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-451181-S34414911302012020700000)
23. GO TO COOLING FAN SYSTEM. Refer to «ON-VEHICLE INSPECTION»(/scion/tc/ii-2010-2013/remont/cooling-fan/#engine-cooling-fan-system-inspection__on-vehicle-inspection)

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 149

Scheme 150

1. READ VALUE USING TECHSTREAM (REGULATOR CONTROL CURRENT) Use the Data List to check if the compressor assembly with pulley is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-451181-S37068168782012020700000). AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Regulator Control Current Compressor assembly with pulley signal / Min.: 0 A Max.: 0.997 A Value changes between 0 A and 0.997 A in accordance with compressor assembly with pulley operation Check this item with the engine idling and A/C switch on. OK The display is as specified in the normal condition column. Result Proceed to OK (When troubleshooting according to Problem Symptoms Table) A OK (When troubleshooting according to DTC output) B NG C B --> See step 5 C --> See step 2 A --> See step 4
2. INSPECT COMPRESSOR ASSEMBLY WITH PULLEY Remove the compressor assembly with pulley. Refer to «REMOVAL»(ref-451191-S17698822632012020700000). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 2 (SOL+) - 1 (SOL-) 20°C (68°F) 10 to 11 ohms NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY - AIR CONDITIONING AMPLIFIER ASSEMBLY AND BODY GROUND) Disconnect the B8 compressor 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 C32-13 (SOL+) - B8-2 (SOL+) Always Below 1 ohms C32-13 (SOL+) - Body ground Always 10 kohms or higher B8-1 (SOL-) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-451181-S34414911302012020700000)
5. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-451191-S05937696272012020700000)
6. REPLACE COMPRESSOR ASSEMBLY WITH PULLEY. Refer to «REMOVAL»(ref-451191-S17698822632012020700000)

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 151

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 152

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 153

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 154

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 155

See also:
• ON-VEHICLE INSPECTION