Air Conditioning System (Diagnostic Codes & Circuit Tests): Overview Lexus GX J150

DESCRIPTION

The cooler thermistor (room temperature sensor) for the front seat 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 front room temperature. 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 room temperature sensor and reads voltage changes as the resistance of the room temperature sensor changes. This sensor also sends the appropriate signals to the air conditioning amplifier assembly.

Scheme 245

Scheme 246

1. READ VALUE USING TECHSTREAM (ROOM TEMPERATURE SENSOR) Use the Data List to check if the cooler thermistor (room temperature sensor) is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-524121-S13390577292013012800000) . AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Room Temperature Sensor Cooler thermistor (room temperature sensor) / Min.: -6.5°C (20.3°F) Max.: 57.25°C (135.05°F) Actual room temperature for front seat displayed Open in the circuit: -6.5°C (20.3°F). Short in the circuit: 57.25°C (135.05°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 the DTC) B NG C B --> See step 4 C --> See step 2 A --> See step 6
2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) Remove the cooler thermistor (room temperature sensor). Refer to «REMOVAL»(ref-524260-S14269293832013012800000) . 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 sensor 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 (refer to the graph). NG --> See step 5 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the G15 sensor connector. Disconnect the G13 amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition G15-1 - G13-29 (TR) Always Below 1 ohms G15-2 - G13-34 (SG-1) G13-29 (TR) - Body ground Always 10 kohms or higher G13-34 (SG-1) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 4
4. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
5. REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR). Refer to «REMOVAL»(ref-524260-S14269293832013012800000)
6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)

The cooler thermistor (ambient temperature sensor) is installed in the front part of the cooler condenser assembly to detect the ambient temperature and control the air conditioning auto mode. The sensor connected to the air conditioning amplifier assembly 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 assembly. The resistance of the cooler thermistor (ambient temperature sensor) changes in accordance with the cooler thermistor temperature (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 cooler thermistor (ambient temperature sensor) and reads voltage changes as changes in the resistance of the cooler thermistor (ambient temperature sensor).

Scheme 247

Scheme 248

1. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR) Use the Data List to check if the cooler thermistor (ambient temperature sensor) is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-524121-S13390577292013012800000) . AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sensor Cooler thermistor (ambient temperature sensor) / 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). 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 the DTC) B NG C B --> See step 4 C --> See step 2 A --> See step 7
2. INSPECT COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR) Remove the cooler thermistor (ambient temperature sensor). Refer to «REMOVAL»(ref-524260-S01402951732013012800000) . 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 sensor 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 (refer to the graph). NG --> See step 5 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the A1 sensor connector. Disconnect the G13 amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A1-1 - G13-5 (TAM) Always Below 1 ohms A1-2 - G13-13 (SG-2) G13-5 (TAM) - Body ground Always 10 kohms or higher G13-13 (SG-2) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 6
4. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
5. REPLACE COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR). Refer to «REMOVAL»(ref-524260-S01402951732013012800000)
6. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
7. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)

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 evaporator 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 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 No. 1 cooler thermistor and reads voltage changes as the resistance of the No. 1 cooler thermistor changes. This sensor is used for frost prevention.

Scheme 249

Scheme 250

Scheme 251

1. READ VALUE USING TECHSTREAM (NO. 1 COOLER THERMISTOR) Use the Data List to check if the No. 1 cooler thermistor is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-524121-S13390577292013012800000) . 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 the DTC) B NG C B --> See step 5 C --> See step 2 A --> See step 7
2. INSPECT NO. 1 COOLER THERMISTOR Remove the No. 1 cooler thermistor. Refer to «DISASSEMBLY»(ref-524260-S31786912652013012800000) . 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 sensor 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 (refer to the graph). NG --> See step 4 OK: Go to next step
3. INSPECT AIR CONDITIONING HARNESS ASSEMBLY Remove the air conditioning harness assembly. Refer to «DISASSEMBLY»(ref-524260-S09285825982013012800000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z1-6 (TEA) - 2 Always Below 1 ohms z1-5 (SGA) - 1 Always Below 1 ohms z1-6 (TEA) - Body ground Always 10 kohms or higher z1-5 (SGA) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to No. 1 Cooler Thermistor) *b Front view of wire harness connector (to Air Conditioning Amplifier Assembly) NG --> See step 6 OK --> See step 5
4. REPLACE NO. 1 COOLER THERMISTOR. Refer to «DISASSEMBLY»(ref-524260-S31786912652013012800000)
5. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
6. REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to «DISASSEMBLY»(ref-524260-S09285825982013012800000)
7. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)

The No. 2 air conditioning harness assembly (rear evaporator temperature sensor) is installed on the evaporator in the rear air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the rear air conditioning. It sends signals to the air conditioning amplifier assembly. The signals change in accordance with the resistance of the No. 2 air conditioning harness assembly (rear evaporator temperature sensor). 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 No. 2 air conditioning harness assembly (rear evaporator temperature sensor) and reads voltage changes as the resistance of the No. 2 air conditioning harness assembly (rear evaporator temperature sensor) changes. This sensor is used for frost prevention.

Scheme 252

Scheme 253

1. READ VALUE USING TECHSTREAM (REAR EVAPORATOR TEMPERATURE SENSOR) Use the Data List to check if the rear evaporator temperature sensor is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-524121-S13390577292013012800000) . AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sens (Rear) Rear evaporator temperature sensor / Min.: -29.7°C (-21.46°F) Max.: 59.55°C (139.19°F) Actual rear 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 the DTC) B NG C B --> See step 5 C --> See step 2 A --> See step 4
2. INSPECT NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (REAR EVAPORATOR TEMPERATURE SENSOR) Remove the No. 2 air conditioning harness assembly (rear evaporator temperature sensor). Refer to «DISASSEMBLY»(ref-524260-S21804301482013012800000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 7 (-) - 8 (+) -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 sensor 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 (refer to the graph). NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (REAR EVAPORATOR TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the Q13 harness connector. Disconnect the G12 amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q13-8 (+) - G12-4 (TEC) Always Below 1 ohms Q13-7 (-) - G12-19 (SGND) Always Below 1 ohms Q13-8 (+) - Body ground Always 10 kohms or higher Q13-7 (-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)
5. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
6. REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (REAR EVAPORATOR TEMPERATURE SENSOR). Refer to «DISASSEMBLY»(ref-524260-S21804301482013012800000)
7. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)

The smog ventilation sensor is installed on the front of the cooler condenser assembly to control automatic air inlet. This sensor detects CO and HC in the emission gas and transmits signals to the air conditioning amplifier assembly.

Scheme 254

The cooler thermistor (rear room temperature sensor) is installed in the rear panel. It detects the rear cabin temperature to control the air conditioning AUTO mode. The resistance of the cooler thermistor (rear room temperature sensor) changes in accordance with the rear 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 cooler thermistor (rear room temperature sensor) and reads voltage changes as the resistance of the cooler thermistor (rear room temperature sensor) changes.

Scheme 255

Scheme 256

1. READ VALUE USING TECHSTREAM (REAR ROOM TEMPERATURE SENSOR) Use the Data List to check if the rear room temperature sensor is functioning properly. Refer to «DATA LIST / ACTIVE TEST»(ref-524121-S13390577292013012800000) . AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Room Temp Sensor (Rear) Cooler thermistor (rear room temperature sensor) / Min.: -6.5°C (20.3°F) Max.: 57.25°C (135.05°F) Actual rear cabin temperature displayed Open in the circuit: -6.5°C (- 20.3°F). Short in the circuit: 57.25°C (135.05°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 the DTC) B NG C B --> See step 5 C --> See step 2 A --> See step 4
2. INSPECT COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR) Remove the cooler thermistor (rear room temperature sensor). Refer to «REMOVAL»(ref-524260-S23064127552013012800000) . 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 Resistance *b Allowable Range *c Temperature NOTE: Even slightly touching the sensor 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 (refer to the graph). NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the G12 amplifier connector. Disconnect the Q21 sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q21-1 - G12-17 (TR) Always Below 1 ohms Q21-2 - G12-7 (SG-6) Always Below 1 ohms Q21-1 - Body ground Always 10 kohms or higher Q21-2 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)
5. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
6. REPLACE COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR). Refer to «REMOVAL»(ref-524260-S23064127552013012800000)
7. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)

SYSTEM DESCRIPTION

The ECM sends the engine speed signal to the air conditioning amplifier assembly via CAN communication.

The air conditioning amplifier assembly reads the difference between compressor speed and engine speed. When the difference becomes too large, the air conditioning amplifier assembly determines that the cooler compressor assembly is locked and turns the magnet clutch assembly off.

Scheme 257

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 higher). 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 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 258

Scheme 259

Scheme 260

Scheme 261

1. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - BATTERY AND BODY GROUND) Disconnect the A2 sensor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A2-3 (+) - Body ground Engine switch on (IG) 4.75 to 5.25 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A2-1 (-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Air Conditioning Pressure Sensor) NG --> See step 4 OK: Go to next step
2. CHECK AIR CONDITIONER PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Reconnect the A2 sensor connector. Remove the air conditioning amplifier assembly with its connectors still connected. Refer to «REMOVAL»(ref-524260-S29534205702013012800000) . Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition G13-9 (PRE) - Body ground Engine switch on (IG) 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) Measure the voltage when the following conditions are met. MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting MAX COOL 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 (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 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 G13-9 (PRE) - Body ground Engine switch on (IG) A/C switch on 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 the DTC) B NG C B --> See step 16 C --> See step 11 A --> See step 21
4. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the G13 amplifier connector. Disconnect the A2 sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A2-1 (-) - G13-13 (SG-2) Always Below 1 ohms A2-3 (+) - G13-10 (S5-3) Always Below 1 ohms G13-13 (SG-2) - Body ground Always 10 kohms or higher G13-10 (S5-3) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 16
5. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the G13 amplifier connector. Disconnect the A2 sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A2-2 (PR) - G13-9 (PRE) Always Below 1 ohms G13-9 (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. 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-524260-S35710843342013012800000) . NEXT: Go to next step
8. CHECK FOR DTC Check for DTCs when the following conditions are met. Refer to «DTC CHECK / CLEAR»(ref-524121-S36455431922013012800000) . MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting MAX COOL 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, 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 operation of the ambient temperature sensor and 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 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 FAULTY)
9. CHECK AIR CONDITIONER PRESSURE SENSOR Install a manifold gauge set. Reconnect the A2 sensor connector. Remove the air conditioning amplifier assembly with its connectors still connected. Refer to «REMOVAL»(ref-524260-S29534205702013012800000) . Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition G13-9 (PRE) - G13-13 (SG-2) Engine switch on (IG) 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 switch on (IG) Refrigerant pressure abnormal (below 0.176 MPa [1.8 kgf/cm 2 , 25.5 psi]) Below 0.63 V Engine switch on (IG) 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 17 OK --> See step 16
10. REPAIR AIR CONDITIONING SYSTEM LEAK Identify the area where refrigerant leaks. Refer to «REPLACEMENT»(ref-524260-S35710843342013012800000) . Repair the identified area of the air conditioning system. Evacuate the air conditioning system. NEXT --> See step 18
11. 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-524260-S35710843342013012800000) . 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 the DTC. NEXT: Go to next step
12. CHECK FOR DTC Check for DTCs when the following conditions are met. Refer to «DTC CHECK / CLEAR»(ref-524121-S36455431922013012800000) . MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting MAX COOL 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, 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 operation of the ambient temperature sensor and 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 13 OK --> See step 19
13. REPLACE COOLER EXPANSION VALVE Replace the cooler expansion valve with a new or normally functioning one. Refer to «DISASSEMBLY»(ref-524260-S09285825982013012800000) . 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
14. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT»(ref-524260-S35710843342013012800000) . NEXT: Go to next step
15. CHECK FOR DTC Check for DTCs when the following conditions are met. MEASUREMENT CONDITION Item Condition Engine Speed 2000 rpm Vehicle Doors Fully open Temperature Setting MAX COOL 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, 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 operation of the ambient temperature sensor and 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 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 cooler condenser assembly or pipes. OK DTC B1423 is not output. NG --> See step 20 OK --> END (COOLER EXPANSION VALVE IS FAULTY)
16. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-524260-S29534205702013012800000)
17. REPLACE AIR CONDITIONER PRESSURE SENSOR. Refer to «REMOVAL»(ref-524260-S40439411892013012800000)
18. CHARGE REFRIGERANT. Refer to «REPLACEMENT»(ref-524260-S35710843342013012800000)
19. REPLACE COOLER DRYER. Refer to «REMOVAL»(ref-524260-S34032891152013012800000)
20. CLEAN OR REPLACE COOLER CONDENSER ASSEMBLY OR PIPES. Refer to «REMOVAL»(ref-524260-S34032891152013012800000)
21. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-524121-S04171627272013012800000)

The No. 2 air conditioning radiator damper servo sub-assembly (front passenger side air mix damper servo) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the air mix damper (for front passenger side) to any position. As a result, the air mix damper (for front passenger side) varies the mixture of hot air from the heater core and cold air from the evaporator so that the temperature of the air blowing toward the front passenger side is as requested.

HINT

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

Scheme 262

The recirculation damper servo sub-assembly sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the air inlet damper to any position, which controls the intake air settings (fresh, fresh/recirculation and recirculation).

HINT

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

Scheme 263

The No. 1 air conditioning radiator damper servo sub-assembly (mode damper servo) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the air outlet damper to any position, which controls the air outlet changes.

HINT

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

Scheme 264

The No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix damper servo) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the air mix damper (for driver side) to any position. As a result, the air mix damper (for driver side) varies the mixture of hot air from the heater core and cold air from the evaporator so that the temperature of the air blowing toward the front passenger side is as requested.

HINT

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

Scheme 265

The rear No. 1 cooling unit damper servo sub-assembly (rear 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 rear air mix damper to any position. As a result, the amount of air passing through the heater core after passing through the evaporator is adjusted and the temperature of the air blowing toward the rear is controlled.

The air conditioning amplifier communicates with the servo through the No. 2 air conditioning harness assembly.

HINT

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

Scheme 266

The rear No. 2 cooling unit damper servo sub-assembly (rear mode damper servo) 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 rear air outlet damper to any position, which controls the air outlet modes.

The air conditioning amplifier assembly communicates with the servo through the No. 2 air conditioning harness.

HINT

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

Scheme 267

The smog ventilation sensor detects NOx in the emission gas and transmits signals to the air conditioning amplifier assembly. Based on the signals, the air conditioning amplifier assembly performs automatic air inlet control (Fresh, Fresh/Recirculation or Recirculation mode).

The air conditioning harness assembly connects the air conditioning amplifier assembly and each servo motor. 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 the damper position information to the air conditioning amplifier assembly.

1. *1: w/ Rear Air Conditioning System

Scheme 268

Scheme 269

The automatic light control sensor (solar sensor), which is installed on the upper side of the instrument panel, detects sunlight and controls the air conditioning in auto mode. The output current from the solar sensor varies according to the amount of sunlight. When the amount of sunlight increases, the output current increases. As the amount of sunlight decreases, the output current decreases. The air conditioning amplifier assembly detects the output current from the solar sensor.

Scheme 270

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

w/ Navigation System

This circuit consists of the display and navigation module display and air conditioning amplifier assembly. When the display and navigation module display is operated, signals are transmitted to the air conditioning amplifier assembly through the CAN communication system.

If the CAN communication system malfunctions, the air conditioning amplifier assembly does not operate when the display and navigation module display is operated.

w/o Navigation System

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

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

Scheme 271

Scheme 272

When the cooler control switch sub-assembly is pushed, the blower motor sub-assembly and cooler magnet valve assembly controlled by the air conditioning amplifier assembly and air conditioning amplifier assembly (for the cooling box) operate. If the cooling box assembly does not operate when the cooler control switch sub-assembly is pushed, there may be a problem in the circuit shown below.

Scheme 273

When the air conditioning amplifier assembly is turned on, a magnet clutch assembly signal is sent from the MGC terminal of the air conditioning amplifier assembly. Then, the A/C COMP relay turns on to operate the magnet clutch assembly.

Scheme 274

This circuit consists of the No. 2 air conditioning control assembly and air conditioning amplifier. When the No. 2 air conditioning control assembly 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 No. 2 air conditioning control assembly is operated.

Scheme 275

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

Scheme 276

The rear cooling unit expansion valve (rear magnetic valve) is controlled by the air conditioning amplifier assembly.

Scheme 277

The main power source is supplied to the air conditioning amplifier assembly when the engine switch is turned on (IG). The power source is used for operating the air conditioning amplifier assembly, servo motors, etc.

Scheme 278

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

Scheme 279

See also:
• REMOVAL
• DISASSEMBLY