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Home >> Lexus >> 2025 >> NX 250 FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 22 (Heating / Air Conditioning System - Diagnostic Codes, Circuit Tests & Symptom Tests) >> AIR CONDITIONING SYSTEM (for HEV Model) >> Ambient Temperature Display System [11/2021 - ] >> Procedure

Ambient Temperature Display System [11/2021 - ]: Procedure

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  1. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC P0070-11 and P0070-15 are not output A
      DTC P0070-11 is output B
      DTC P0070-15 is output C

    Result: 

    GO TO DTC P0070-11. Refer to  DTC P0070-11: Ambient Temperature Sensor Circuit Short to Ground [11/2021 - ]  

    Result: 

    GO TO DTC P0070-15. Refer to  DTC P0070-15: Ambient Temperature Sensor Circuit Short to Battery or Open [11/2021 - ]  

    Result: 

    See step  2

  2. INSPECT AMBIENT TEMP. SENSOR (THERMISTOR ASSEMBLY) 

    Refer to INSPECTION [11/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE AMBIENT TEMP. SENSOR (THERMISTOR ASSEMBLY). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMP. SENSOR (THERMISTOR ASSEMBLY) - AIR CONDITIONING AMPLIFIER ASSEMBLY) 
    NOTE:

    During the parked vehicle inspection, perform the inspection with the ignition switch off (do not start the engine and electric motor).

    1. Disconnect the A14 ambient temp. sensor (thermistor assembly) connector.
    2. Disconnect the D53 air conditioning amplifier assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A14-2 - D53-1 (TAM) Always Below 1 Ω
      A14-1 - D53-14 (SG-2) Always Below 1 Ω
      A14-2 or D53-1 (TAM) - Other terminals and body ground Always 10 kΩ or higher
      A14-1 or D53-14 (SG-2) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CLEAR ECU STORED VALUES (THERMISTOR ASSEMBLY DETECTION VALUE) 

    HINT: 

    The air conditioning amplifier assembly reads and memorizes the ambient temp. sensor (thermistor assembly) detection value (THO) from before the ignition switch was turned off for 1 hour after turning the ignition switch off. Therefore, it is necessary to switch off the air conditioning amplifier assembly internal power source and clear the stored values from before the ignition switch was turned off.

    1. Turn the ignition switch off.
      NOTE:
      • Make sure that the wire harness(es) and connector(s) for the vehicle being inspected are connected.
      • After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

        Refer to BEFORE DISCONNECTING BATTERY [11/2021 - ]

        HINT: 

        When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

        Refer to AUTOMATIC LEARNING CHART [11/2021 - ]

    2. Disconnect the cable from the negative (-) auxiliary battery terminal and wait for at least 90 seconds.
    3. Connect the cable to the negative (-) auxiliary battery terminal.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CHECK VALUE OF AMBIENT TEMPERATURE DETECTED BY AMBIENT TEMP. SENSOR (THERMISTOR ASSEMBLY) 
    NOTE:

    Perform the following procedure with the ignition switch ON. (Do not turn the ignition switch to ON (READY).)

    1. Turn the ignition switch to ON and wait for 6 minutes or more.
      NOTE:

      Wait at least 6 minutes for the values of the ambient temp. sensor (thermistor assembly) and thermometer to become stable before taking a measurement.

    2. Measure and make a note of the ambient temperature near the ambient temp. sensor (thermistor assembly) using a thermometer.
      NOTE:
      • Hold the thermometer 50 mm (1.97 in.) from the ambient temp. sensor (thermistor assembly) with its sensing portion at the same height and perpendicular to the ambient temp. sensor (thermistor assembly).
      • Hold the sensor only by its connector. Touching the sensing portion may change the resistance value.
      • When measuring the ambient temperature with a thermometer, do not move the thermometer, touch the sensing portion or allow it to contact the vehicle body.
    3. Make a note of the ambient temperature displayed on the multi-information display in the combination meter assembly.
    4. Compare the values of the ambient temperature measured by the thermometer and the ambient temp. sensor (thermistor assembly).

      OK

      The values of the ambient temperature measured by the thermometer and the ambient temp. sensor (thermistor assembly) are almost the same.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2021 - ]