Air Conditioning System (For Automatic A/c) (Diagnostic Codes & Circuit Tests): Overview Toyota RAV4 IV

DESCRIPTION

The room temperature sensor is installed in the instrument panel to detect the room temperature and control the heater and air conditioner AUTO mode. The resistance of the room temperature sensor changes in accordance with the room temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

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

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Room Temperature Sensor Room temperature sensor / Min.: -6.5°C (20.3°F) Max.: 57.25°C (135.05°F) Actual room temperature is displayed Open circuit: -6.5°C (20.3°F) Short circuit: 57.25°C (135.05°F) OK The display is as specified in the normal condition column. RESULT Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY A: Go to next step
2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) Remove the room temperature sensor. Measure the resistance of the sensor. Standard resistance Tester Connection Condition Specified Condition 1 - 2 10°C (50°F) 3.00 to 3.73 kohms 1 - 2 15°C (59°F) 2.45 to 2.88 kohms 1 - 2 20°C (68°F) 1.95 to 2.30 kohms 1 - 2 25°C (77°F) 1.60 to 1.80 kohms 1 - 2 30°C (86°F) 1.28 to 1.47 kohms 1 - 2 35°C (95°F) 1.00 to 1.22 kohms 1 - 2 40°C (104°F) 0.80 to 1.00 kohms 1 - 2 45°C (113°F) 0.65 to 0.85 kohms 1 - 2 50°C (122°F) 0.50 to 0.70 kohms 1 - 2 55°C (131°F) 0.44 to 0.60 kohms 1 - 2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Touching the sensor even slightly may change the resistance value. Be sure to hold the connector of the sensor. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph). NG --> REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the E21 sensor connector. Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition E21-1 - E37-29 (TR) Always Below 1 ohms E21-2 - E37-34 (SG-1) Always Below 1 ohms E21-1 - Body ground Always 1 Mohms or higher E21-2 - Body ground Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

The ambient temperature sensor is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner. The sensor is connected to the combination meter and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The sensor sends a signal to the air conditioning amplifier via the combination meter. The resistance of the ambient temperature sensor 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 applies a voltage (5 V) to the ambient temperature sensor and reads voltage changes as changes in the resistance of the ambient temperature sensor. The combination meter sends the read signal to the air conditioning amplifier via CAN communication.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Ambient Temp Sensor Ambient temperature sensor / Min.: -23.3°C (-9.94°F) Max.: 65.95°C (150.71°F) Actual ambient temperature is displayed Open circuit: -23.3°C (-9.94°F) Short circuit: 65.95°C (150.71°F) OK The display is as specified in the normal condition column. Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Measure the resistance of the sensor. Standard resistance Tester Connection Condition Specified Condition 1 (OT-) - 2 (OT+) 10°C (50°F) 3.00 to 3.73 kohms 1 (OT-) - 2 (OT+) 15°C (50°F) 2.45 to 2.88 kohms 1 (OT-) - 2 (OT+) 20°C (68°F) 1.95 to 2.30 kohms 1 (OT-) - 2 (OT+) 25°C (77°F) 1.60 to 1.80 kohms 1 (OT-) - 2 (OT+) 30°C (86°F) 1.28 to 1.47 kohms 1 (OT-) - 2 (OT+) 35°C (95°F) 1.00 to 1.22 kohms 1 (OT-) - 2 (OT+) 40°C (104°F) 0.80 to 1.00 kohms 1 (OT-) - 2 (OT+) 45°C (113°F) 0.65 to 0.85 kohms 1 (OT-) - 2 (OT+) 50°C (122°F) 0.50 to 0.70 kohms 1 (OT-) - 2 (OT+) 55°C (131°F) 0.44 to 0.60 kohms 1 (OT-) - 2 (OT+) 60°C (140°F) 0.36 to 0.50 kohms NOTE: Touching the sensor even slightly may change the resistance value. Be sure to hold the connector of the sensor. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph). NG --> REPLACE AMBIENT TEMPERATURE SENSOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - COMBINATION METER) Disconnect the A17 sensor connector. Disconnect the E19 meter connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition A17-2 (OT+) - E19-28 (TEMP) Always Below 1 ohms A17-1 (OT-) - E19-11 (TX1+) Always Below 1 ohms A17-2 (OT+) - Body ground Always 1 Mohms or higher A17-1 (OT-) - Body ground Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE COMBINATION METER

The No. 1 cooler thermistor (evaporator temperature sensor) is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air that has passed through the evaporator and to control the air conditioner. It sends signals to the air conditioning amplifier. The signals change in accordance with the resistance of the No. 1 cooler thermistor (evaporator temperature sensor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier applies a voltage (5 V) to the No. 1 cooler thermistor (evaporator temperature sensor) and reads voltage changes as changes in the resistance of the No. 1 cooler thermistor (evaporator temperature sensor). This sensor is used for frost prevention.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Evaporator Fin Thermistor Evaporator temperature sensor / Min.: -29.7°C (-21.46°F) Max.: 59.55°C (139.19°F) Actual evaporator temperature is displayed Open circuit: -29.7°C (-21.46°F) Short circuit: 59.55°C (139.19°F) OK The display is as specified in the normal condition column. Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT NO. 1 COOLER THERMISTOR (EVAPORATOR TEMPERATURE SENSOR) Remove the No. 1 cooler thermistor. Measure the resistance of the thermistor. Standard resistance Tester Connection Condition Specified Condition 1 - 2 -10°C (14°F) 7.30 to 9.10 kohms 1 - 2 -5°C (23°F) 5.65 to 6.95 kohms 1 - 2 0°C (32°F) 4.40 to 5.35 kohms 1 - 2 5°C (41°F) 3.40 to 4.15 kohms 1 - 2 10°C (50°F) 2.70 to 3.25 kohms 1 - 2 15°C (59°F) 2.14 to 2.58 kohms 1 - 2 20°C (68°F) 1.71 to 2.05 kohms 1 - 2 25°C (77°F) 1.38 to 1.64 kohms 1 - 2 30°C (86°F) 1.11 to 1.32 kohms NOTE: Touching the thermistor even slightly may change the resistance value. Be sure to hold the connector of the thermistor. When measuring, the thermistor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph). NG --> REPLACE NO. 1 COOLER THERMISTOR (EVAPORATOR TEMPERATURE SENSOR) OK --> REPLACE AIR CONDITIONING HARNESS ASSEMBLY

The solar sensor, which is installed on the upper side of the instrument panel, detects sunlight and controls the air conditioning AUTO mode. The output voltage from the solar sensor varies in accordance with the amount of sunlight. When the sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases.

The air conditioning amplifier detects changes in the output voltage from the solar sensor.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Solar Sensor (P side) Passenger side solar sensor / Min.: 0, Max.: 255 Passenger side temperature increases as brightness increases - OK The display is as specified in the normal condition column. Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT COOLER (SOLAR SENSOR) THERMISTOR Remove the solar sensor. Measure the resistance of the sensor. Connect the ohmmeter's positive (+) lead to terminal 1 and the negative (-) lead to terminal 2 of the solar sensor. Standard resistance Tester Connection Condition Specified Condition 1 (S5) - 2 (TSP) Sensor exposed to electric light Below 1ohms 1 (S5) - 2 (TSP) Sensor covered with cloth 10 kohms or higher NOTE: The connection procedure for using a digital tester such as an electrical tester is shown above. When using an analog tester, connect the positive (+) lead to terminal 2 and the negative (-) lead to terminal 1 of the solar sensor. HINT: As the inspection light is moved away from the sensor, the voltage decreases. Use an incandescent light for the inspection. Position it about 30 cm (11.8 in.) from the solar sensor. NG --> REPLACE COOLER (SOLAR SENSOR) THERMISTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SOLAR SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the F1 sensor connector. Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition E37-32 (TSP) - F1-2 (TSP) Always Below 1 ohms E37-31 (S5-4) - F1-1 (S5) Always Below 1 ohms E37-32 (TSP) - Body ground Always 1 Mohms or higher E37-31 (S5-4) - Body ground Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER

This sensor sends 1 pulse per engine revolution to the air conditioning amplifier. If the ratio of the compressor speed divided by the engine speed is smaller than a predetermined value, the air conditioning amplifier turns the compressor off, and the indicator blinks at approximately 1 second intervals.

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1. CHECK AIR CONDITIONING AMPLIFIER (LOCK SIGNAL) Remove the air conditioning amplifier with its connectors still connected. Check the waveform of the amplifier connector. OK Waveform is as shown in the illustration. Item Content Symbol (Terminal No.) LOCK (E37-8) - SG-2 (E37-35) Tool Setting 500 mV/DIV., 20 msec./DIV. Condition Engine idling Blower switch LO A/C switch ON (magnet clutch ON) Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT COOLER COMPRESSOR ASSEMBLY Disconnect the B47 compressor connector. Measure the resistance of the sensor. Standard resistance Tester Connection Condition Specified Condition 1 (SSR+) - 2 (SSR-) 20°C (68°F) 65 to 125 ohms NG --> REPLACE COOLER COMPRESSOR ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (COOLER COMPRESSOR ASSEMBLY - AIR CONDITIONING AMPLIFIER) Disconnect the B47 compressor connector. Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition B47-1 (SSR+) - E37-8 (LOCK) Always Below 1 ohms B47-2 (SSR-) - E37-35 (SG-2) Always Below 1 ohms B47-1 (SSR+) - Body ground Always 10 kohms or higher B47-2 (SSR-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER

This DTC is stored when 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 more). The air conditioner pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs the refrigerant pressure signal to the air conditioning amplifier. The air conditioning amplifier converts the signal to pressure 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 can also be stored if there is no refrigerant in the cycle.

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1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the A21 air conditioner pressure sensor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition A21-3 (+) - Body ground Ignition switch ON 4.75 to 5.25 V NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A21-1 (-) - Body ground Always Below 1 ohms NG --> See step 6 OK: Go to next step
3. INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Reconnect the A21 air conditioner pressure sensor connector. Remove the air conditioning amplifier with its connectors still connected. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition E37-9 (PRE) - Body ground Ignition switch ON A/C switch off 0.7 to 4.8 V 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 7 OK: Go to next step
4. INSPECT AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Measure the voltage when the following conditions are satisfied. MEASUREMENT CONDITION Item Condition Engine Speed 1500 rpm Vehicle Doors Fully open Temperature Setting Lo Blower Speed Hi A/C Switch On R/F Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If refrigerant pressure on the high pressure side becomes extremely high during the inspection (if the voltage exceeds 4.8 V), the fail-safe function stops 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 operation of the ambient temperature sensor and the evaporator temperature sensor 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 Switch Condition Specified Condition E37-9 (PRE) - Body ground Engine idling Blower switch LO A/C switch on 0.7 to 4.8 V NG --> See step 13 OK --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
5. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the E37 air conditioning amplifier connector. Disconnect the A21 air conditioner pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A21-3 (+) - E37-30 (S5-3) Always Below 1 ohms E37-30 (S5-3) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
6. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the E37 air conditioning amplifier connector. Disconnect the A21 air conditioner pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A21-1 (-) - E37-35 (SG-2) Always Below 1 ohms E37-35 (SG-2) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
7. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the E37 air conditioning amplifier connector. Disconnect the A21 air conditioner pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A21-2 (PR) - E37-9 (PRE) Always Below 1 ohms E37-9 (PRE) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. INSPECT FOR AIR CONDITIONING SYSTEM LEAK Install a manifold gauge set. Recover the refrigerant from the air conditioning system using a refrigerant recovery unit. 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 12 OK: Go to next step
9. CHARGE REFRIGERANT Add an appropriate amount of refrigerant.Refer to «REPLACEMENT»(ref-493477-S39991979602012081000000) . NEXT: Go to next step
10. RECHECK DTC Recheck for the DTC when the following conditions are satisfied. MEASUREMENT CONDITION Item Condition Engine Speed 1500 rpm Vehicle Doors Fully open Temperature Setting Lo Blower Speed Hi A/C Switch On R/F Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 operation of the ambient temperature sensor and the evaporator temperature sensor 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 leaks. The root cause of excessive refrigerant may be adding refrigerant when the level was insufficient. Therefore, identify and repair the area where refrigerant leaks as necessary. NG --> See step 11 OK --> END
11. CHECK AIR CONDITIONER PRESSURE SENSOR Install a manifold gauge set. Reconnect the A21 air conditioner pressure sensor connector. Remove the air conditioning amplifier with its connectors still connected. Turn the ignition switch ON. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E37-9 (PRE) - E37-35 (SG-2) Refrigerant pressure: Normal pressure (less than 3.025 MPa [30.9 kgf/cm 2 , 438.6 psi] and more than 0.176 MPa [1.8 kgf/cm 2 , 25.5 psi]) 0.76 to 4.74 V Refrigerant pressure: Abnormal (less than 0.176 MPa [1.8 kgf/cm 2 , 25.5 psi]) Below 0.76 V Refrigerant pressure: Abnormal (more than 3.025 MPa [30.9 kgf/cm 2 , 438.6 psi]) 4.74 V or higher NG --> REPLACE AIR CONDITIONER PRESSURE SENSOR OK --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
12. REPAIR AIR CONDITIONING SYSTEM LEAK Identify the area where refrigerant leaks.Refer to «REPLACEMENT»(ref-493477-S39991979602012081000000) . Repair the identified area of the air conditioning system. Evacuate the air conditioning system. NEXT --> CHARGE REFRIGERANT
13. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Evacuate the air conditioning system. Add an appropriate amount of refrigerant.Refer to «REPLACEMENT»(ref-493477-S39991979602012081000000) . 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 check for the DTC. NEXT: Go to next step
14. RECHECK DTC Recheck for the DTC when the following conditions are satisfied. MEASUREMENT CONDITION Item Condition Engine Speed 1500 rpm Vehicle Doors Fully open Temperature Setting Lo Blower Speed Hi A/C Switch On R/F Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 operation of the ambient temperature sensor and the evaporator temperature sensor 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 the DTC. If the DTC is not output after this procedure, it indicates that the cooler dryer in the cooler condenser assembly 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 15 OK --> REPLACE COOLER DRYER
15. REPLACE COOLER EXPANSION VALVE Replace the cooler expansion valve with a normal one.Refer to «DISASSEMBLY»(ref-493477-S32949498052012081000000) . HINT: Replace the cooler expansion valve with a normal one because the cooler expansion valve is either stuck or clogged. NEXT: Go to next step
16. CHARGE REFRIGERANT Add an appropriate amount of refrigerant.Refer to «REPLACEMENT»(ref-493477-S39991979602012081000000) . NEXT: Go to next step
17. RECHECK DTC Recheck for the DTC when the following conditions are satisfied. MEASUREMENT CONDITION Item Condition Engine Speed 1500 rpm Vehicle Doors Fully open Temperature Setting Lo Blower Speed Hi A/C Switch On R/F Switch Recirculation Interior Temperature 25 to 35°C (77 to 95°F) NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be stored. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) 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 operation of the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If refrigerant pressure is not normal after replacing the expansion valve with a normal one, the cooler condenser assembly or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the cooler condenser assembly or pipes. OK DTC B1423 is not output. NG --> REPLACE COOLER CONDENSER ASSEMBLY OK --> END

The solar sensor, which is installed on the upper side of the instrument panel, detects sunlight and controls the air conditioning AUTO mode. The output voltage from the solar sensor varies in accordance with the amount of sunlight. When the sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases.

The air conditioning amplifier detects changes in the output voltage from the solar sensor.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Solar Sensor (D side) Driver side solar sensor / Min.: 0, Max.: 255 Driver side temperature increases as brightness increases - OK The display is as specified in the normal condition column. Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT SOLAR SENSOR Remove the solar sensor. Measure the resistance of the sensor. Connect the ohmmeter's positive (+) lead to terminal 1 and the negative (-) lead to terminal 3 of the solar sensor. Standard resistance Tester Connection Condition Specified Condition 1 (S5) - 3 (TSD) Sensor exposed to electric light Below 1ohms 1 (S5) - 3 (TSD) Sensor covered with cloth 10 kohms or higher NOTE: The connection procedure for using a digital tester such as an electrical tester is shown above. When using an analog tester, connect the positive (+) lead to terminal 3 and the negative (-) lead to terminal 1 of the solar sensor. HINT: As the inspection light is moved away from the sensor, the voltage decreases. Use an incandescent light for the inspection. Position it about 30 cm (11.8 in.) from the solar sensor. NG --> REPLACE SOLAR SENSOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SOLAR SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the F1 sensor connector. Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition E37-33 (TSD) - F1-3 (TSD) Always Below 1 ohms E37-31 (S5-4) - F1-1 (S5) Always Below 1 ohms E37-33 (TSD) - Body ground Always 1 Mohms or higher E37-31 (S5-4) - Body ground Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER

The air mix damper servo sends pulse signals to indicate the damper position to the air conditioning amplifier. The air conditioning amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (for front passenger side) 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 blown air.

HINT

Confirm that there are no mechanical problems because this DTC can be output when either a damper link or damper is mechanically locked.

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The damper servo (air inlet control) sends pulse signals to indicate the damper position to the air conditioning amplifier. The air conditioning amplifier activates the motor (normal or reverse) based on these signals to move the air inlet control damper to the appropriate position, which controls the intake air settings (FRESH, FRESH / RECIRCULATION and RECIRCULATION).

HINT

Confirm that there are no mechanical problems because this DTC can be output when either a damper link or damper is mechanically locked.

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The damper servo sends pulse signals to indicate the damper position to the air conditioning amplifier. The air conditioning amplifier activates the motor (normal or reverse) based on these signals to move the mode damper to the appropriate position, which controls the air outlet modes.

HINT

Confirm that there are no mechanical problems because this DTC can be output when either a damper link or damper is mechanically locked.

Scheme 72

The air mix damper servo sends pulse signals to indicate the damper position to the air conditioning amplifier. The air conditioning amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (for driver side) 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 blown air.

HINT

Confirm that there are no mechanical problems because this DTC can be output when either a damper link or damper is mechanically locked.

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In this circuit, the compressor receives a refrigerant compression demand signal from the air conditioning amplifier. Based on this signal, the compressor changes the degree of refrigerant compression.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the items below in the Data List, and read the value displayed on the Techstream. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Regulator Control Current Regulator control current / Min.: 0 A Max.: 0.997 A Value changes between 0 A and 0.997 A in accordance with compressor operation - OK The display is as specified in the normal condition column. Result Result Proceed to NG A OK (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE C --> REPLACE AIR CONDITIONING AMPLIFIER A: Go to next step
2. INSPECT COOLER COMPRESSOR ASSEMBLY Disconnect the compressor connector. Measure the resistance of the connector. Standard resistance Tester Connection Condition Specified Condition 1 (SOL-) - 2 (SOL+) 25°C (77°F) 10.1 to 11.1 ohms NG --> REPLACE COOLER COMPRESSOR ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (COOLER COMPRESSOR ASSEMBLY - AIR CONDITIONING AMPLIFIER) Disconnect the B23 compressor connector. Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Condition Specified Condition B23-2 (SOL+) - E37-2 (SOL+) Always Below 1 ohms B23-2 (SOL+) - Body Ground Always 1 Mohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (COOLER COMPRESSOR ASSEMBLY - BODY GROUND) Disconnect the B23 compressor connector. Measure the resistance of the wire harness side connector. Standard resistance Tester Connection Condition Specified Condition B23-1 (SOL-) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE AIR CONDITIONING AMPLIFIER

The flow sensor is built into the compressor, and outputs a signal indicating the flow rate of the refrigerant. The air conditioning amplifier 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.

*1: As the flow sensor measures the flow rate of the refrigerant in the air conditioning system, it is necessary to turn the ignition switch to ON in order to check the state of the flow sensor.

Scheme 78

Scheme 79

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream on. Check the flow sensor voltage in the Data List. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Flow sensor Flow sensor/ Min.: 0.0 V, Max.: 5.0 V Flow sensor voltage displayed Open circuit: 4.7 V or more Short circuit: 0.3 V or less RESULT Result Proceed to 4.7 V or more: Open circuit (A/C switch is on) A 0.3 V or less: Short circuit (A/C switch is on) A Circuit is not open or shorted B B --> See step 5 A: Go to next step
2. CHECK HARNESS AND CONNECTOR (COOLER COMPRESSOR ASSEMBLY - AIR CONDITIONING AMPLIFIER) Disconnect the B66 compressor connector. Disconnect the E37 amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition B66-3 (QUFL) - E37-7 (FLOQ) Always Below 1 ohms B66-1 (S5FL) - E37-10 (S5-1) Always Below 1 ohms B66-2 (SGFL) - E37-13 (SG-4) Always Below 1 ohms E37-7 (FLOQ) - Body ground Always 10 kohms or higher E37-10 (S5-1) - Body ground Always 10 kohms or higher E37-13 (SG-4) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. REPLACE COOLER COMPRESSOR ASSEMBLY Replace the cooler compressor assembly with a normal one.Refer to «REMOVAL»(ref-493477-S17055995762012081000000) . NEXT: Go to next step
4. CHECK FOR DTC Clear the DTCs.Refer to «DTC CHECK / CLEAR»(ref-493443-S30876032102012081000000) . Check for DTCs.Refer to «DTC CHECK / CLEAR»(ref-493443-S30876032102012081000000) . OK DTC B1479 is not output. NG --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY OK --> END
5. READ VALUE USING TECHSTREAM Check the flow sensor voltage in the Data List. Air conditioning amplifier Tester Display Measurement Item / Range Normal Condition Diagnostic Note Flow sensor Flow Sensor/ Min.: 0.0 V, Max.: 5.0 V Flow sensor voltage displayed Open circuit: 4.7 V or more Short circuit: 0.3 V or less RESULT Result Proceed to Sensor is stuck in an intermediate position Engine idling A/C switch is off Sensor voltage is 3.76 V or less and does not change for 8.5 minutes or more A Sensor is stuck at zero position Engine idling A/C switch is on Sensor voltage is 3.76 V or more and does not change for 8.5 minutes or more A Sensor is not stuck B B --> See step 7 A: Go to next step
6. REPLACE COOLER COMPRESSOR ASSEMBLY Replace the cooler compressor assembly with a normal one.Refer to «REMOVAL»(ref-493477-S17055995762012081000000) . NEXT: Go to next step
7. CHECK FOR DTC Clear the DTCs.Refer to «DTC CHECK / CLEAR»(ref-493443-S30876032102012081000000) . Check for DTCs.Refer to «DTC CHECK / CLEAR»(ref-493443-S30876032102012081000000) . OK DTC B1479 is not output. NG --> REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY OK --> END

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

Scheme 80

The air conditioning amplifier communicates data with the ECM and combination meter through the CAN communication system.

Scheme 81

This circuit consists of the air conditioning control and the air conditioning amplifier. When the air conditioning control is operated, signals are transmitted to the air conditioning amplifier through the LIN communication system.

If the LIN communication system malfunctions, the air conditioning amplifier does not operate even if the air conditioning control is operated.

Scheme 82

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

Scheme 83

Scheme 84

Scheme 85

Scheme 86

Scheme 87

Scheme 88

Scheme 89

1. PERFORM ACTIVE TEST USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Active Test, and then check that the blower motor operates. Air conditioning amplifier Tester Display Test Part Control Range Diagnostic Note Blower Motor Blower motor Min.: 0, Max.: 31 - Result Result Proceed to NG (blower motor does not operate) A NG (blower motor operates but does not change speed) B OK C B --> See step 6 C --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE A: Go to next step
2. INSPECT FUSE (HTR) Remove the HTR H-fuse from the engine room No. 2 relay block. Measure the resistance of the H-fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND) Disconnect the E53 motor connector. Measure the resistance of the wire harness side connector. Standard resistance Tester Connection Condition Specified Condition E53-1 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY) Disconnect the E53 motor connector. Measure the voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition E53-3 (+B) - Body ground Ignition switch ON 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK BLOWER MOTOR Disconnect the E37 amplifier connector. Connect the E53 motor connector. Measure the voltage of the connector. Standard voltage Tester Connection Condition Specified Condition E53-2 (SI) - Body ground Ignition switch ON 4.5 to 5.5 V NG --> REPLACE BLOWER MOTOR OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND) Disconnect the E37 amplifier connector. Measure the voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition E37-23 (BLW) - Body ground Ignition switch ON Blower switch OFF 4.5 to 5.5 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. CHECK AIR CONDITIONING AMPLIFIER Remove the air conditioning amplifier with its connectors still connected. Check the waveform of the amplifier connector. OK Waveform is as shown in the illustration. HINT: The waveform varies with the blower level. Item Content Symbol (Terminal No.) BLW (E37-23) - GND (E37-14) Tool Setting 1 V/DIV., 500 μsec./DIV. Condition Ignition switch ON Blower switch LO NG --> REPLACE AIR CONDITIONING AMPLIFIER OK --> REPLACE BLOWER MOTOR

When the A/C switch is turned on, the magnet clutch ON signal is sent from the air conditioning amplifier. Then the magnet clutch relay turns on to operate the magnet clutch.

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

1. PERFORM ACTIVE TEST USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream ON. Select the item below in the Active Test and then check that the magnet clutch relay operates. Air conditioning amplifier Tester Display Test Part Control Range Diagnostic Note Magnetic Clutch Relay Magnet clutch relay Magnet clutch relay / OFF, ON Operating sound can be heard OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE NG: Go to next step
2. INSPECT FUSE (ECU-IG1) Remove the ECU-IG1 fuse from the instrument panel junction block. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
3. INSPECT MAGNET CLUTCH RELAY (Marking: MG CLT) Remove the magnet clutch relay from the engine room No. 1 relay block. Measure the resistance of the relay. Standard resistance Tester Connection Condition Specified Condition 3 - 5 When battery voltage is not applied to terminals 1 and 2 10 kohms or higher 3 - 5 When battery voltage is applied to terminals 1 and 2 Below 1 ohms NG --> REPLACE MAGNET CLUTCH RELAY OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY) Disconnect the E37 amplifier connector. Measure the voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition E37-20 (MGC) - Body ground Ignition switch ON 11 to 14 V E37-20 (MGC) - Body ground Ignition switch off Below 1 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK AIR CONDITIONING AMPLIFIER (MGC VOLTAGE) Remove the air conditioning amplifier with its connectors still connected. Measure the voltage of the connector. Standard voltage Tester Connection Condition Specified Condition E37-20 (MGC) - Body ground Engine idling Blower switch LO A/C switch OFF 11 to 14 V E37-20 (MGC) - Body ground Engine idling Blower switch LO A/C switch ON Below 1.5 V NG --> REPLACE AIR CONDITIONING AMPLIFIER OK: Go to next step
6. CHECK MAGNET CLUTCH ASSEMBLY Disconnect the B47 magnet clutch connector. Connect the battery's positive (+) lead to terminal 3 of the magnet clutch and the negative (-) lead to the body ground. OK Magnet clutch is engaged. NG --> REPLACE MAGNET CLUTCH ASSEMBLY OK --> REPAIR OR REPLACE WIRE HARNESS (MAGNET CLUTCH - ECU-IG1)

PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the quick heater assembly installed on the radiator heater unit.

Scheme 95

This is the main power source supplied to the air conditioning amplifier when the ignition switch is ON. This power source is used for operating components, such as the air conditioning amplifier and servo motors.

Scheme 96

Scheme 97

Scheme 98

1. INSPECT FUSE (ECU-IG2) Remove the ECU-IG2 fuse from the instrument panel junction block. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY) Disconnect the E37 amplifier connector. Measure the voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition E37-1 (IG+) - Body ground Ignition switch ON 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND) Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connector. Standard resistance Tester Connection Condition Specified Condition E37-14 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

This is the back-up power source circuit for the air conditioning amplifier. Power is supplied even when the ignition switch is turned off and is used for functions such as the diagnostic trouble code memory.

Scheme 99

Scheme 100

Scheme 101

1. INSPECT FUSE (ECU-B2) Remove the ECU-B2 fuse from the engine room No. 2 relay block. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY) Disconnect the E37 amplifier connector. Measure the voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition E37-21 (B) - Body ground Always 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND) Disconnect the E37 amplifier connector. Measure the resistance of the wire harness side connector. Standard resistance Tester Connection Condition Specified Condition E37-14 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE