AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System), Diagnostic DTC:B1411/11

DTC Code DTC Name
B1411/11 Room Temperature Sensor Circuit

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.

DTC Code DTC Detection Condition Trouble Area
B1411/11 An open or short in the room temperature sensor circuit.

  • Cooler thermistor (room temperature sensor)

  • Harness or connector

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A002Q3UE60
*a Cooler Thermistor (Room Temperature Sensor)
*b Air Conditioning Amplifier Assembly

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Use the Data List to check if the cooler thermistor (room temperature sensor) is functioning properly.

      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 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

    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

  2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)


    1. Remove the room temperature sensor Click here.

      A002LZAE01

    2. 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 kΩ
      15°C (59°F) 2.45 to 2.88 kΩ
      20°C (68°F) 1.95 to 2.30 kΩ
      25°C (77°F) 1.60 to 1.80 kΩ
      30°C (86°F) 1.28 to 1.47 kΩ
      35°C (95°F) 1.00 to 1.22 kΩ
      40°C (104°F) 0.80 to 1.00 kΩ
      45°C (113°F) 0.65 to 0.85 kΩ
      50°C (122°F) 0.50 to 0.70 kΩ
      55°C (131°F) 0.44 to 0.60 kΩ
      60°C (140°F) 0.36 to 0.50 kΩ

      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.

      Tech Tips

      As the temperature increases, the resistance decreases (refer to the graph).


    NG

    REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)


    1. Disconnect the H38 sensor connector.

      A002P34E01

    2. Disconnect the H46 amplifier connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H38-1 - H46-29 (TR) Always Below 1 Ω
      H38-2 - H46-34 (SG-1)
      H46-29 (TR) - Body ground Always 10 kΩ or higher
      H46-34 (SG-1) - Body ground
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Room Temperature Sensor)
      *2

      Rear view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR