Lexus NX: Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
NOTICE:
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If the auxiliary battery voltage is low, the PTC heater, seat heater system (w/ Seat Heater System) and climate control seat system (w/ Climate Control Seat System) may not operate. When "High Power Consumption Partial Limit On AC/Heater Operation." is displayed on the multi-information display in the combination meter assembly, inspect the auxiliary battery, referring to On-vehicle Inspection for the charging system.
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HINT:
If the auxiliary battery voltage is low, "Operation Limitation Control History Count (Level 1)" and "Operation Limitation Control History Count (Level 2) is counted.
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- PTC Heater
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Seat heater system (w/ Seat Heater System)
If the seat heater system does not operate normally, refer to the troubleshooting.
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Climate control seat system (w/ Climate Control Seat System)
If the climate control seat system does not operate normally, refer to the troubleshooting.
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If the auxiliary battery voltage is low, the PTC heater may not operate. Refer to Data List for the power steering system.
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for Manual Tilt and Manual Telescopic Steering Column
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for Power Tilt and Power Telescopic Steering Column
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for Manual Tilt and Manual Telescopic Steering Column
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When the auxiliary battery is disconnected, or servo motor or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.
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HINT:
- Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
- Inspect the fuses and relays related to this system before inspecting the suspected areas below.
| Symptom | Suspected Area | Link |
|---|---|---|
| All functions of the air conditioning system do not operate. | IG power source circuit | |
| Back-up power source circuit | | |
| LIN communication circuit | | |
| Air conditioning amplifier assembly | | |
| Air flow control: No blower operation. | Blower motor circuit | |
| Air conditioning control assembly | | |
| Air conditioning amplifier assembly | | |
| Air flow control: No blower control. | Blower motor circuit | |
| Air conditioning control assembly | | |
| Air conditioning amplifier assembly | | |
| Air flow control: Insufficient air flow. | Blower motor circuit | |
| Air conditioning amplifier assembly | | |
| Temperature control: Cooling effectiveness is poor. | Refrigerant gas volume check using the Techstream | |
| Refrigerant volume | | |
| Refrigerant pressure | | |
| Cooler expansion valve | | |
| Compressor with motor assembly | | |
| Air conditioning amplifier assembly | | |
| Temperature control: No cool air comes out. | Refrigerant gas volume check using the Techstream | |
| Refrigerant volume | | |
| Refrigerant pressure | | |
| Air conditioner pressure sensor circuit | | |
| Air mix damper control servo motor circuit (for driver side) | | |
| Air mix damper control servo motor circuit (for front passenger side) | | |
| Evaporator temperature sensor circuit | | |
| Room temperature sensor circuit | | |
| Ambient temperature sensor circuit | | |
| Check customize setting "Set Temperature Shift" | | |
| LIN communication circuit | | |
| Cooler expansion valve | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Engine wire | | |
| Compressor with motor assembly | | |
| Air conditioning amplifier assembly | | |
| Hybrid vehicle control ECU | | |
| Inverter with converter assembly | | |
| ECM | | |
| Temperature control: No warm air comes out. | Air mix damper control servo motor circuit (for driver side) | |
| Air mix damper control servo motor circuit (for front passenger side) | | |
| Evaporator temperature sensor circuit | | |
| Room temperature sensor circuit | | |
| Ambient temperature sensor circuit | | |
| Heater water pump circuit | | |
| Check customize setting "Set Temperature Shift" | | |
| LIN communication circuit | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Radiator unit sub-assembly | | |
| Air conditioning amplifier assembly | | |
| Hybrid vehicle control ECU | | |
| ECM | | |
| Temperature control: Output air is warmer or cooler than the set temperature or response is slow. | Refrigerant gas volume check using the Techstream | |
| Refrigerant volume | | |
| Refrigerant pressure | | |
| Solar sensor circuit (for driver side) (for Triple Beam Headlight) | | |
| Solar sensor circuit (for driver side) (for Single Beam Headlight) | | |
| Solar sensor circuit (for front passenger side) (for Triple Beam Headlight) | | |
| Solar sensor circuit (for front passenger side) (for Single Beam Headlight) | | |
| Room temperature sensor circuit | | |
| Ambient temperature sensor circuit | | |
| Air mix damper control servo motor circuit (for driver side) | | |
| Air mix damper control servo motor circuit (for front passenger side) | | |
| Air inlet damper control servo motor circuit | | |
| LIN communication circuit | | |
| Radiator unit sub-assembly | | |
| Cooler expansion valve | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| No. 1 blower damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Air conditioning amplifier assembly | | |
| Hybrid vehicle control ECU | | |
| ECM | | |
| Temperature control: No temperature control. (only Max. cool or Max. hot) | Air mix damper control servo motor circuit (for driver side) | |
| Air mix damper control servo motor circuit (for front Passenger side) | | |
| Room temperature sensor circuit | | |
| Ambient temperature sensor circuit | | |
| Evaporator temperature sensor circuit | | |
| Solar sensor circuit (for driver side) (for Triple Beam Headlight) | | |
| Solar sensor circuit (for driver side) (for Single Beam Headlight) | | |
| Solar sensor circuit (for front passenger side) (for Triple Beam Headlight) | | |
| Solar sensor circuit (for front passenger side) (for Single Beam Headlight) | | |
| LIN communication circuit | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Air conditioning amplifier assembly | | |
| No air inlet control. | Air inlet damper control servo motor circuit | |
| LIN communication circuit | | |
| No. 1 blower damper servo sub-assembly | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Air conditioning amplifier assembly | | |
| No air flow mode control. | Air outlet damper control servo motor circuit | |
| Rear air outlet damper control servo motor circuit | | |
| LIN communication circuit | | |
| No. 1 air conditioning radiator damper servo sub-assembly | | |
| No. 2 air conditioning radiator damper servo sub-assembly | | |
| Air conditioning harness assembly | | |
| Air conditioning amplifier assembly | | |
| Quick heater assembly does not operate. | "High Power Consumption Partial Limit On AC/Heater Operation" message does not display on the multi-information display in combination meter assembly. | - |
| PTC heater circuit | | |
| Air conditioning amplifier assembly | | |
| Hybrid vehicle control ECU | | |
| ECM | | |
| Integration control and panel assembly (ECO mode switch) does not operate normally. | ECO switch circuit | |
| Air conditioning amplifier assembly | | |
| Diagnostic trouble codes (DTCs) are not recorded. Set mode is cleared when power switch is off. | Back-up power source circuit | |
| Air conditioning amplifier assembly | |
READ NEXT:
Dtc Check / Clear
DTC CHECK / CLEAR DTC CHECK USING TECHSTREAM (a) Connect the Techstream to the DLC3. (b) Turn the power switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Air
Terminals Of Ecu
TERMINALS OF ECU AIR CONDITIONING AMPLIFIER ASSEMBLY (a) Disconnect the I50 air conditioning amplifier assembly connector. (b) Measure the resistance and voltage according to the value(s) in the tabl
Check Mode Procedure
CHECK MODE PROCEDURE REFRIGERANT GAS VOLUME CHECK IN NORMAL OPERATION (CHECK A/C SWITCH INDICATOR AND DTC) *a Example (a) Turn the power switch on (READY). (b) Check that A/C switch indicator
SEE MORE:
Inspection
INSPECTION PROCEDURE 1. INSPECT OUTER MIRROR LH (a) Check the outer mirror heater operation. (1) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 1 - 2 25°C (77°F) 6.8 to 10.2 Ω If the r
How To Proceed With Troubleshooting
CAUTION / NOTICE / HINT HINT:
The power back door system troubleshooting procedure is based on the premise that the smart access system with push-button start (for Entry Function) is operating normally. Check the smart access system with push-button start (for Entry Function) first before trouble
