Air Conditioning (Diagnostic Codes & Circuit Tests): Overview Lexus RX III

DESCRIPTION

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control the air conditioning AUTO mode. The resistance of the room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier 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 appropriate signals to the A/C amplifier. The room temperature sensor is integrated with the room humidity sensor.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER 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 cabin temperature displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C C --> See step 5 B --> See step 4 A: Go to next step
2. INSPECT ROOM TEMPERATURE SENSOR Remove the room temperature sensor. Disconnect the room temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F26-1 - F26-2 10°C (50°F) 3.00 to 3.73 kohms F26-1 - F26-2 15°C (59°F) 2.45 to 2.88 kohms F26-1 - F26-2 20°C (68°F) 1.95 to 2.30 kohms F26-1 - F26-2 25°C (77°F) 1.60 to 1.80 kohms F26-1 - F26-2 30°C (86°F) 1.28 to 1.47 kohms F26-1 - F26-2 35°C (95°F) 1.00 to 1.22 kohms F26-1 - F26-2 40°C (104°F) 0.80 to 1.00 kohms F26-1 - F26-2 45°C (113°F) 0.65 to 0.85 kohms F26-1 - F26-2 50°C (122°F) 0.50 to 0.70 kohms F26-1 - F26-2 55°C (131°F) 0.44 to 0.60 kohms F26-1 - F26-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases ( (Scheme 235)the graph). TEXT IN ILLUSTRATION *1 Component without harness connected (Room Temperature Sensor) *2 Sensing Portion NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F50-29 (TR) - F26-1 Always Below 1 ohms F50-34 (SG-1) - F26-2 Always Below 1 ohms F50-29 (TR) - Body ground Always 10 kohms or higher F50-34 (SG-1) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Room Temperature Sensor) 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-400793-S26530521342011051800000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
6. REPLACE ROOM TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-400783-S36625167112011051800000)

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control the air conditioning AUTO mode. The resistance of the room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier 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 appropriate signals to the A/C amplifier. The room temperature sensor is integrated with the room humidity sensor.

The ambient temperature sensor is installed in front of the condenser. It detects the ambient temperature to control air conditioning AUTO mode. This sensor is connected to the A/C amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the A/C amplifier. 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 A/C amplifier applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER 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 displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C C --> See step 5 B --> See step 4 A: Go to next step
2. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Disconnect the ambient temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A3-1 - A3-2 10°C (50°F) 3.00 to 3.73 kohms A3-1 - A3-2 15°C (59°F) 2.45 to 2.88 kohms A3-1 - A3-2 20°C (68°F) 1.95 to 2.30 kohms A3-1 - A3-2 25°C (77°F) 1.60 to 1.80 kohms A3-1 - A3-2 30°C (86°F) 1.28 to 1.47 kohms A3-1 - A3-2 35°C (95°F) 1.00 to 1.22 kohms A3-1 - A3-2 40°C (104°F) 0.80 to 1.00 kohms A3-1 - A3-2 45°C (113°F) 0.65 to 0.85 kohms A3-1 - A3-2 50°C (122°F) 0.50 to 0.70 kohms A3-1 - A3-2 55°C (131°F) 0.44 to 0.60 kohms A3-1 - A3-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases ( (Scheme 239)the graph). TEXT IN ILLUSTRATION *1 Component without harness connected (Ambient Temperature Sensor) *2 Sensing Portion NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F50-5 (TAM) - A3-2 Always Below 1 ohms F50-13 (SG-2) - A3-1 Always Below 1 ohms F50-5 (TAM) - Body ground Always 10 kohms or higher F50-13 (SG-2) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Ambient Temperature Sensor) 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-400793-S26530521342011051800000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
6. REPLACE AMBIENT TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-400783-S42712404022011051800000)

The ambient temperature sensor is installed in front of the condenser. It detects the ambient temperature to control air conditioning AUTO mode. This sensor is connected to the A/C amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the A/C amplifier. 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 A/C amplifier applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

The evaporator temperature sensor is installed on the evaporator in the air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the air conditioning. It sends appropriate signals to the A/C amplifier. The resistance of the evaporator temperature sensor changes in accordance with the cooled air temperature that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the evaporator temperature sensor and reads voltage changes as the resistance of the evaporator temperature sensor changes. This sensor is used for frost prevention.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER 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 displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C C --> See step 4 B --> See step 5 A: Go to next step
2. INSPECT EVAPORATOR TEMPERATURE SENSOR Remove the evaporator temperature sensor. Disconnect the evaporator temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z16-1 - z16-2 -10°C (14°F) 7.30 to 9.10 kohms z16-1 - z16-2 -5°C (23°F) 5.65 to 6.95 kohms z16-1 - z16-2 0°C (32°F) 4.40 to 5.35 kohms z16-1 - z16-2 5°C (41°F) 3.40 to 4.15 kohms z16-1 - z16-2 10°C (50°F) 2.70 to 3.25 kohms z16-1 - z16-2 15°C (59°F) 2.14 to 2.58 kohms z16-1 - z16-2 20°C (68°F) 1.71 to 2.05 kohms z16-1 - z16-2 25°C (77°F) 1.38 to 1.64 kohms z16-1 - z16-2 30°C (86°F) 1.11 to 1.32 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases ( (Scheme 243)the graph). TEXT IN ILLUSTRATION *1 Component without harness connected (Evaporator Temperature Sensor) *2 Sensing Portion NG --> See step 7 OK: Go to next step
3. INSPECT AIR CONDITIONING HARNESS (A/C AMPLIFIER - EVAPORATOR TEMPERATURE SENSOR) Remove the air conditioning harness. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z6-6 (TE) - z16-2 Always Below 1 ohms z6-5 (SG) - z16-1 Always Below 1 ohms z6-6 (TE) - Body ground Always 10 kohms or higher z6-5 (SG) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Evaporator Temperature Sensor) NG --> See step 8 OK --> See step 6
4. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-400793-S26530521342011051800000)
6. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
7. REPLACE EVAPORATOR TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-400783-S16036889822011051800000)
8. REPLACE AIR CONDITIONING HARNESS. Refer to «DISASSEMBLY»(ref-400783-S39113695842011051800000)

The evaporator temperature sensor is installed on the evaporator in the air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the air conditioning. It sends appropriate signals to the A/C amplifier. The resistance of the evaporator temperature sensor changes in accordance with the cooled air temperature that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the evaporator temperature sensor and reads voltage changes as the resistance of the evaporator temperature sensor changes. This sensor is used for frost prevention.

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

Scheme 246

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

SYSTEM DESCRIPTION

The ECM sends the engine speed signal to the A/C amplifier via CAN communication.

The A/C amplifier reads the difference between compressor speed and engine speed. When the difference becomes too large, the A/C amplifier determines that the compressor is locked, and turns the magnetic clutch off.

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1. CHECK CAN COMMUNICATION SYSTEM Use the Techstream to check if the CAN communication system is functioning normally. Result Result Proceed to CAN DTC is not output A CAN DTC is output B B --> See step 4 A: Go to next step
2. INSPECT A/C COMPRESSOR (A/C LOCK SENSOR) Disconnect the A/C compressor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition D7-1 (SSR+) - D7-2 (SSR-) 20°C (68°F) 160 to 320 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (A/C Compressor) NG --> See step 7 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C LOCK SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F50-8 (LOCK) - D7-1 (SSR+) Always Below 1 ohms F50-13 (SG-2) - D7-2 (SSR-) Always Below 1 ohms F50-8 (LOCK) - Body ground Always 10 kohms or higher F50-13 (SG-2) - Body ground Always 10 kohms or higher Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Compressor) C --> See step 6 B --> See step 5 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
4. GO TO CAN COMMUNICATION SYSTEM. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-400834-S14071915672011051800000)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-400793-S26530521342011051800000)
6. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
7. REPLACE A/C COMPRESSOR (A/C LOCK SENSOR). Refer to «REMOVAL»(ref-400783-S29353979272011051800000)

The ECM sends the engine speed signal to the A/C amplifier via CAN communication.

The A/C amplifier reads the difference between compressor speed and engine speed. When the difference becomes too large, the A/C amplifier determines that the compressor is locked, and turns the magnetic clutch off.

This DTC is output when refrigerant pressure on the high pressure side is extremely low (0.19 MPa (2.0 kgf/cm 2 , 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm 2 , 455 psi) or more). The A/C pressure sensor is installed on the high pressure line. It detects refrigerant pressure to output a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to a pressure value according to the sensor characteristics to control the compressor.

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1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the A/C pressure sensor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A7-3 (+) - Body ground Engine switch on (IG) 4.75 to 5.25 V TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Pressure Sensor) 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 A7-1 (-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Pressure Sensor) NG --> See step 6 OK: Go to next step
3. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Reconnect the A/C pressure sensor connector. Remove the A/C amplifier with the connectors still connected. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition F50-9 (PRE) - Body ground Engine switch on (IG) (A/C: off) 0.73 to 4.84 V HINT: If the voltage is not as specified, there may be a malfunction in the A/C amplifier, A/C pressure sensor or wire harness. It is also possible that the amount of refrigerant may not be appropriate. TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 7 OK: Go to next step
4. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Measure the voltage when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch on R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure line becomes extremely high during the inspection (if the voltage exceeds 4.84 V), the fail-safe function stops compressor operation. Therefore, measure the voltage before the fail-safe function operates. It is necessary to measure the voltage over a period 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 signals from 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 Condition Specified Condition F50-9 (PRE) - Body ground Engine switch on (IG) (A/C: on) 0.73 to 4.84 V Result Result Proceed to OK (When troubleshooting according to the DTC) A OK (When troubleshooting according to Problem Symptoms Table) B NG C TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) C --> See step 13 B --> See step 19 A --> See step 20
5. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A7-3 (+) - F50-10 (S5-3) Always Below 1 ohms F50-10 (S5-3) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 20
6. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A7-1 (-) - F50-13 (SG-2) Always Below 1 ohms F50-13 (SG-2) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 20
7. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A7-2 (PR) - F50-9 (PRE) Always Below 1 ohms F50-9 (PRE) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK FOR A/C SYSTEM LEAK Install the manifold gauge set. Recover the refrigerant from the A/C system using a refrigerant recovery unit. Evacuate the A/C system and check that vacuum can be maintained. OK Vacuum can be maintained in the A/C system. HINT: If vacuum cannot be maintained in the A/C system, there may be a refrigerant leak. In this case, it is necessary to repair or replace the leaking part of the A/C system. NG --> See step 12 OK: Go to next step
9. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-400783-S08693988022011051800000) . NEXT: Go to next step
10. RECHECK FOR DTC Recheck for the DTC when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch on R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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. Result Result Proceed to DTC B1423/23 is output A DTC B1423/23 is not output B NOTE: If the DTC was set 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 any refrigerant leaks as necessary. B --> END A: Go to next step
11. INSPECT A/C PRESSURE SENSOR Install the manifold gauge set. Reconnect the A/C pressure sensor connector. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition F50-9 (PRE) - F50-13 (SG-2) Refrigerant pressure: Normal pressure (less than 3.187 MPa [462 psi] and more than 0.39 MPa [57 psi]) 1.0 to 4.912 V TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 24 OK --> See step 20
12. REPAIR A/C SYSTEM LEAK Identify the area where refrigerant leaks from. Refer to «REPLACEMENT - Step 4»(ref-400783-S08693988022011051800000) . Repair the identified area of the A/C system. Evacuate the A/C system. NEXT --> See step 21
13. INSPECT COOLING FAN SYSTEM Check that the cooling fan(s) operates normally. HINT: Refer to Cooling Fan Circuit. Refer to «Cooling Fan Circuit»(ref-400828-S21322224722011051800000) . NG --> REPAIR COOLING FAN SYSTEM OK: Go to next step
14. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Evacuate the A/C system. Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-400783-S08693988022011051800000) . 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, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs. NEXT: Go to next step
15. RECHECK FOR DTC Recheck for the DTC when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch on R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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, 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, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant. In this case, to complete the repair, it is necessary to replace the cooler dryer. Result Result Proceed to DTC B1423/23 is output A DTC B1423/23 is not output B B --> See step 22 A: Go to next step
16. REPLACE EXPANSION VALVE Replace the expansion valve with a new or a known good one. Refer to «DISASSEMBLY»(ref-400783-S39113695842011051800000) . HINT: Replace the expansion valve with a new or a known good one because the expansion valve is either stuck or clogged. NEXT: Go to next step
17. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-400783-S08693988022011051800000) . NEXT: Go to next step
18. RECHECK FOR DTC Recheck for the DTC when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch on R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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 new or a known good one, the condenser or pipes may be clogged with dirt, dust or other contaminants. In this case, clean or replace the condenser or pipes. Result Result Proceed to DTC B1423/23 is not output A DTC B1423/23 is output B B --> See step 23 A --> END
19. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-400793-S26530521342011051800000)
20. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
21. CHARGE REFRIGERANT. Refer to «REPLACEMENT - Step 2»(ref-400783-S08693988022011051800000)
22. REPLACE COOLER DRYER. Refer to «DISASSEMBLY»(ref-400783-S32650797782011051800000)
23. REPLACE CONDENSER. Refer to «REMOVAL»(ref-400783-S08629792942011051800000)
24. REPLACE A/C PRESSURE SENSOR Replace the A/C pressure sensor. Refer to «REMOVAL»(ref-400783-S23370413202011051800000) . HINT: Since the A/C pressure sensor cannot be inspected while it is removed from the vehicle, replace the A/C pressure sensor with a new or a known good one and check that the condition returns to normal. NEXT: Go to next step
25. RECHECK FOR DTC Recheck for the DTC when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch on R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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. Result Result Proceed to DTC B1423/23 is not output A DTC B1423/23 is output B B --> See step 20 A --> END

This DTC is output when refrigerant pressure on the high pressure side is extremely low (0.19 MPa (2.0 kgf/cm 2 , 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm 2 , 455 psi) or more). The A/C pressure sensor is installed on the high pressure line. It detects refrigerant pressure to output a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to a pressure value according to the sensor characteristics to control the compressor.

The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (front passenger side) 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 passenger side is controlled.

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

HINT

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

Scheme 262

The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (front passenger side) 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 passenger side is controlled.

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

HINT

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

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

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

HINT

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

Scheme 263

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

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

HINT

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

The air outlet control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the mode damper to any position, which controls the air outlet switching.

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

HINT

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

Scheme 264

The air outlet control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the mode damper to any position, which controls the air outlet switching.

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

HINT

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

The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (driver side) 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 driver side is controlled.

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

HINT

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

Scheme 265

The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (driver side) 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 driver side is controlled.

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

HINT

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

In this circuit, the A/C compressor receives a refrigerant compression demand signal from the A/C amplifier.

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

Scheme 266

Scheme 267

Scheme 268

Scheme 269

Scheme 270

1. INSPECT A/C COMPRESSOR (SOLENOID VALVE) Disconnect the A/C compressor (solenoid valve) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition D9-2 (SOL+) - D9-1 (SOL-) 20°C (68°F) 10 to 11 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (A/C Compressor (Solenoid Valve)) NG --> See step 6 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (A/C COMPRESSOR (SOLENOID VALVE) - BODY GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition D9-1 (SOL-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Compressor (Solenoid Valve)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (A/C COMPRESSOR (SOLENOID VALVE) - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F50-2 (SOL+) - D9-2 (SOL+) Always Below 1 ohms F50-2 (SOL+) - Body ground Always 10 kohms or higher Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Compressor (Solenoid Valve)) C --> See step 5 B --> See step 4 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-400793-S26530521342011051800000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
6. REPLACE A/C COMPRESSOR (SOLENOID VALVE). Refer to «REMOVAL»(ref-400783-S29353979272011051800000)

In this circuit, the A/C compressor receives a refrigerant compression demand signal from the A/C amplifier.

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

The smog ventilation sensor detects NOx in the emission gas and transmits signals to the A/C amplifier. Based on the signals, the A/C amplifier performs automatic air inlet control (FRESH, FRESH/RECIRCULATION or RECIRCULATION mode).

The smog ventilation sensor detects NOx in the emission gas and transmits signals to the A/C amplifier. Based on the signals, the A/C amplifier performs automatic air inlet control (FRESH, FRESH/RECIRCULATION or RECIRCULATION mode).

The A/C mass flow sensor, which is mounted on the A/C compressor, is used to detect the amount of refrigerant flow. The A/C mass flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send it to the A/C amplifier. The voltage value sent from the A/C mass flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The A/C amplifier supplies 5 V to the A/C mass flow sensor and monitors changes in the voltage value sent from the A/C mass flow sensor. The A/C amplifier then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.

Scheme 271

Scheme 272

Scheme 273

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Flow Sensor A/C mass flow sensor / Min.: 0 V Max.: 5 V A/C on, Blower switch HI: 0.7 to 3.8 V A/C off, Blower switch off: 3.8 to 4.2 V A/C mass flow sensor is malfunctioning when a constant value between 0.7 and 4.2 V is displayed continuously for more than 4 seconds. 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 (When a constant value between 0.7 and 4.2 V is displayed continuously for more than 4 seconds) C C --> See step 3 B --> See step 5 A: Go to next step
2. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note A/C Cutoff Signal A/C control cutoff signal / OFF or ON A/C switch on: OFF A/C switch off: ON - Result Result Proceed to Value in Data List indicates OFF A Value in Data List indicates ON B B --> See step 6 A: Go to next step
3. REPLACE A/C COMPRESSOR (A/C MASS FLOW SENSOR) Replace the A/C compressor (A/C mass flow sensor). Refer to «REMOVAL»(ref-400783-S29353979272011051800000) . HINT: Since the A/C compressor (A/C mass flow sensor) cannot be inspected while it is removed from the vehicle, replace the A/C compressor (A/C mass flow sensor) with a new or a known good one and check that the condition returns to normal. Check for the DTC. Result Result Proceed to DTC B1479/79 is not output A DTC B1479/79 is output B B --> See step 4 A --> END
4. CHECK HARNESS AND CONNECTOR (A/C COMPRESSOR (A/C MASS FLOW SENSOR) - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F50-7 (FLOQ) - D10-3 (QUFL) Always Below 1 ohms F50-13 (SG-2) - D10-2 (SGFL) Always Below 1 ohms F50-30 (S5-1) - D10-1 (S5FL) Always Below 1 ohms F50-7 (FLOQ) - Body ground Always 10 kohms or higher F50-13 (SG-2) - Body ground Always 10 kohms or higher F50-30 (S5-1) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Compressor (A/C Mass Flow Sensor)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-400793-S26530521342011051800000)

The A/C mass flow sensor, which is mounted on the A/C compressor, is used to detect the amount of refrigerant flow. The A/C mass flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send it to the A/C amplifier. The voltage value sent from the A/C mass flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The A/C amplifier supplies 5 V to the A/C mass flow sensor and monitors changes in the voltage value sent from the A/C mass flow sensor. The A/C amplifier then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.

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

Scheme 274

Scheme 275

Scheme 276

1. INSPECT A/C AMPLIFIER Remove the A/C amplifier with the connectors still connected. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z6-2 (BUS G) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 4 OK: Go to next step
2. INSPECT A/C AMPLIFIER Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition z6-4 (B BUS) - z6-2 (BUS G) Engine switch off Below 1 V z6-4 (B BUS) - z6-2 (BUS G) Engine switch on (IG) 11 to 14 V z6-3 (BUS) - z6-2 (BUS G) Engine switch on (IG) Pulse generation TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 5 OK --> See step 3
3. REPLACE AIR CONDITIONING HARNESS. Refer to «DISASSEMBLY»(ref-400783-S39113695842011051800000)
4. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(ref-400783-S15121641442011051800000)

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

The solar sensor is installed on the upper side of the instrument panel. It detects sunlight to control air conditioning AUTO mode. The output voltage from the solar sensor varies in accordance with the amount of sunlight. When the amount of sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases. The A/C amplifier detects changes in the output voltage from the solar sensor.

The solar sensor is installed on the upper side of the instrument panel. It detects sunlight to control air conditioning AUTO mode. The output voltage from the solar sensor varies in accordance with the amount of sunlight. When the amount of sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases. The A/C amplifier detects changes in the output voltage from the solar sensor.

Scheme 277

The solar sensor is installed on the upper side of the instrument panel. It detects sunlight to control air conditioning AUTO mode. The output voltage from the solar sensor varies in accordance with the amount of sunlight. When the amount of sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases. The A/C amplifier detects changes in the output voltage from the solar sensor.

w/ Navigation System

1. A/C control panel switch signals are sent to the display and navigation module display via AVC-LAN communication. The display and navigation module display then sends these signals to the A/C amplifier via CAN communication.

w/o Navigation System

1. A/C control panel switch signals are sent to the multi-display assembly CAN communication. The multi-display assembly then sends these signals to the A/C amplifier via CAN communication.

Scheme 278

Scheme 279

1. w/ Navigation System
2. w/o Navigation System

w/ Navigation System

1. A/C control panel switch signals are sent to the display and navigation module display via AVC-LAN communication. The display and navigation module display then sends these signals to the A/C amplifier via CAN communication.

w/o Navigation System

1. A/C control panel switch signals are sent to the multi-display assembly CAN communication. The multi-display assembly then sends these signals to the A/C amplifier via CAN communication.

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

Scheme 280

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

When the A/C amplifier is turned on, a magnetic clutch ON signal is sent from the MGC terminal of the A/C amplifier. Then, the MG/CLT relay turns on to operate the magnetic clutch.

Scheme 281

When the A/C amplifier is turned on, a magnetic clutch ON signal is sent from the MGC terminal of the A/C amplifier. Then, the MG/CLT relay turns on to operate the magnetic clutch.

The main power source is supplied to the A/C amplifier when the engine switch is on (IG).

The power source is used for operating the A/C amplifier and servo motor, etc.

Scheme 282

The main power source is supplied to the A/C amplifier when the engine switch is on (IG).

The power source is used for operating the A/C amplifier and servo motor, etc.

The back-up power source circuit for the A/C amplifier is shown below. Power is supplied even when the engine switch is turned off. The power is used for diagnostic trouble code memory etc.

Scheme 283

The back-up power source circuit for the A/C amplifier is shown below. Power is supplied even when the engine switch is turned off. The power is used for diagnostic trouble code memory etc.