Problem Symptoms Table [03/2023 - ]
WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
- Perform the inspection when the vehicle is at ambient temperature. If this is not done, there could be a risk of injury depending on the location being inspected.
- Inspect the fuses and relays related to this system before inspecting the suspected areas below.
- The air conditioning system uses the CAN communication system. First, confirm that there is no malfunction in the CAN communication system. Refer to the How to Proceed with Troubleshooting procedure.
- VEHICLE CHECK ITEMS
HINT:
- You can reduce the number of systems to check by using the results of the following operation check.
- Perform the following checks based on Customer Feedback and the vehicle condition.
- The customer's opinion may not be consistent with the actual problem (eg: the cooling performance of the air conditioner is bad → actually, the wind volume is weak). It is important to check the problem symptoms accurately and judge correctly based on various sources of information.
- Judgment as to whether the air conditioner panel is normal or abnormal can be judged by checking if the indicator illuminates or turns off when the switch is operated.
- During servo motor initialization, the AUTO indicator light comes on, and then turns off when initialization has finished.
- If the performance of the air conditioner is poor or there is a foul odor, check for clogging in the clean air filter.
Malfunction Operation/Function
Common Function of Cool and Heater Function Only Cool Air Function Only Heater Function Suspected Area A/C Switch Operation Blower Operation Recirculation/Fresh Function Air Outlet Changing Function x o o o x x Go to "Problem Symptoms Table: Air Conditioning Control" o o o o x o Go to "Problem Symptoms Table: Cooling Function" o o o o o x Go to "Problem Symptoms Table: Heater Function" o x o o x x Go to "Problem Symptoms Table: Blower Control" o o x o x x Go to "Problem Symptoms Table: Air Inlet Control" o o o x x x Go to "Problem Symptoms Table: Air Outlet Control" x x x x x x Air Conditioning Amplifier Assembly or Air Conditioner Unit Assembly is Defective - AIR CONDITIONING CONTROL
Symptom Suspected Area Link Air conditioning system cannot be operated using radio and display receiver assembly - (With the exception of the switch indicators, no inputs are reflected when other switches operated)
- CAN communication line
- +B or ground in air conditioning amplifier assembly circuit
- Air conditioning amplifier assembly
- Radio and display receiver assembly
- Harness or connector
Refer to Operation not Accepted Even If Air Conditioning Switch is Operated [11/2021 - ] Air conditioning system cannot be operated using radio and display receiver assembly - (Air conditioning system display operates)
- Radio and display receiver assembly
Refer to REMOVAL [11/2021 - ] Air conditioning system cannot be operated using radio and display receiver assembly immediately after starting the hybrid system - (Air conditioning system display operates) (Only AUTO indicator illuminates)
(A/C switch indicator does not illuminate)
- Refer to "INITIALIZATION"
Refer to INITIALIZATION [11/2021 - ] A/C switch indicator does not illuminate - Air conditioning amplifier assembly
- Radio and display receiver assembly
- Servo motor
- Damper and damper link
- Refrigerant pressure
- Ambient temperature
Refer to A/C Switch Indicator does not Turn On [11/2021 - ] - COOLING FUNCTION
Symptom Suspected Area Link Cool air is not discharged - (Air is discharged)
- Compressor with motor assembly
- Refrigerant pressure
- Refrigerant volume
- Cooler condenser assembly
- Cooling fan system
- Damper and damper link
- Evaporator temperature sensor
Refer to No Cooling at All [11/2021 - ] - Cooling effectiveness is poor
- Cooling response is slow
- Drive mode select switch (combination switch assembly)
- Compressor with motor assembly
- Refrigerant volume
- Cooler condenser assembly
- Cooling fan system
- Damper and damper link
- Solar sensor (automatic light control sensor)
- High inlet air temperature
- Harness or connector
Refer to Cooling is Poor [11/2021 - ] Temperature of outlet air is cooler on left or right side - (When same temperature set for both sides)
- Compressor with motor assembly
- Refrigerant volume
- Damper and damper link
- Solar sensor (automatic light control sensor)
- Harness or connector
Refer to Air Vent Temperature does not Change and Right Vent is Different from Left and Vice Versa (Same Left/Right Temperature Setting) [11/2021 - ] - HEATER FUNCTION
Symptom Suspected Area Link - No warm air comes out (Blower control is normal)
- Outlet air temperature does not increase (Blower control is normal)
- Engine coolant temperature
- Refrigerant volume
- Damper and damper link
- Warm-up control
- Heater radiator unit sub-assembly
Refer to No Heating at All [11/2021 - ] Temperature of outlet air is warmer on left or right side - (When same temperature set for both sides)
- Damper and damper link
- Blockage in heater radiator unit sub-assembly
- Harness or connector
Refer to Air Vent Temperature does not Change and Right Vent is Different from Left and Vice Versa (Same Left/Right Temperature Setting) [11/2021 - ] - BLOWER CONTROL
Symptom Suspected Area Link No air flows from the registers - Blower motor with fan sub-assembly
- Air conditioning amplifier assembly
- Warm-up control
- Engine coolant temperature sensor
- Harness or connector
Refer to Blower Motor does not Operate [11/2021 - ] Airflow volume cannot be changed - Air conditioning amplifier assembly
- Blower motor with fan sub-assembly
- Harness or connector
Refer to Blower Motor Circuit [11/2021 - ] - Airflow volume is constantly low
- Airflow volume sometimes becomes low
- Drive mode select switch (combination switch assembly)
- Blower motor with fan sub-assembly
- Air conditioning amplifier assembly
- Clean air filter
- Evaporator or heater radiator fins
- Evaporator temp. sensor
- Aspirator pipe not connected properly
- Harness or connector
Refer to Weak Blower Output [11/2021 - ] - AIR INLET CONTROL
Symptom Suspected Area Link - Recirculation/fresh mode changes without permission
- Recirculation/fresh mode light blinks
- Customize setting*
- Ambient temperature
- Refrigerant pressure
- Air conditioning pressure sensor circuit
- Engine coolant temperature
Refer to Recirculated/Fresh Air Modes Switch without User Input [11/2021 - ] - Air inlet mode cannot be changed between recirculation/fresh
- Exhaust gas odors can be smelled when air inlet mode set to recirculation mode
- Servo motor
- Damper and damper link
- Engine coolant temperature
- Air conditioner unit assembly
Refer to Recirculated/Fresh Air Modes do not Switch [11/2021 - ] *: except USA and Canada
- AIR OUTLET CONTROL
Symptom Suspected Area Link Air outlet mode cannot be changed - (Air outlet display changes)
- Servo motor
- Damper link
- Air conditioner unit assembly
Refer to Air Vent cannot be Switched [11/2021 - ] Air outlet mode cannot be changed - (Air outlet display does not change)
- Radio and display receiver assembly
Refer to REMOVAL [11/2021 - ] - DEFROSTER CONTROL
Symptom Suspected Area Link Windshield frequently fogs up - Compressor with motor assembly
- Refrigerant volume
- Servo motor
- Damper and damper link
- Cooler expansion valve
- Mechanical locking of damper and damper link
Refer to Front Window Fogging [11/2021 - ]