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AIR CONDITIONING SYSTEM, Diagnostic DTC:B1411

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DTC Code DTC Name
B1411 Room Temperature Sensor Circuit
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DESCRIPTION

The cooler thermistor (room temperature sensor) is installed in the instrument panel to detect the cabin temperature, which is used to control the air conditioning system. The resistance of the cooler thermistor (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 air conditioning amplifier assembly applies voltage (5 V) to the cooler thermistor (room temperature sensor) and reads voltage changes due to changes in the resistance of the cooler thermistor (room temperature sensor).

DTC No. Detection Item DTC Diagnosis condition Trouble Area Memory
B1411 Room Temperature Sensor Circuit

  • Diagnosis condition: Ambient temperature is 30°C (86 °F) or more

  • Malfunction status: Open or short in room temperature sensor circuit

  • Detection time: None (Present malfunction), continuously for 4 seconds or more (Past malfunction)

  • Cooler thermistor (room temperature sensor)

  • Harness or connector

  • Air conditioning amplifier assembly

 Memorized
Tip:

If the cabin temperature is approximately -18.6°C (-1.48°F) or lower, DTC B1411 may be output even though the system is normal.

Table 1. *a Cooler Thermistor (Room Temperature Sensor) *b Air Conditioning Amplifier Assembly
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WIRING DIAGRAM

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PROCEDURE


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    READ VALUE USING GTS (ROOM TEMPERATURE SENSOR)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    5. Read the Data List according to the display on the GTS.


      1. Body Electrical > Air Conditioner > Data List
        Tester Display Measurement Item Range Normal Condition Diagnostic Note
        Room Temperature Sensor Cooler (room temp. sensor) thermistor

        Min.: -6.50°C (20.30°F)

        Max.: 57.25°C (135.05°F)

        		 Actual cabin temperature displayed

        Cooler thermistor system malfunction


        • When open circuit: -6.50°C (20.30°F)

        • When short circuit: 57.25°C (135.05°F)



      1. Body Electrical > Air Conditioner > Data List
        Tester Display
        Room Temperature Sensor




      OK
      The display is as specified in the normal condition column.
      Result
      Proceed to
      OK
      NG

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    INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)


    1. Remove the cooler thermistor (room temperature sensor).

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    2. Inspect the cooler thermistor (room temperature sensor).

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      Result
      Proceed to
      OK
      NG

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    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - COOLER THERMISTOR (ROOM TEMPERATURE SENSOR))


    1. Disconnect the G64 air conditioning amplifier assembly connector.

    2. Disconnect the G36 cooler thermistor (room temperature sensor) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G64-14 (TR) - G36-1 Always Below 1 Ω
      G64-1 (SG-1) - G36-2 Always Below 1 Ω
      G64-14 (TR) or G36-1 - Other terminals and body ground Always 10 kΩ or higher
      G64-1 (SG-1) or G36-2 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLYClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR