AIR CONDITIONING SYSTEM, Diagnostic DTC:B1411

DTC Code DTC Name
B1411 Room Temperature Sensor Circuit

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 (-22°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

Tech Tips

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.

WIRING DIAGRAM

B004A5BE91
*a Cooler Thermistor (Room Temperature Sensor)
*b Air Conditioning Amplifier Assembly

PROCEDURE


  1. 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.


      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)

      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

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

  2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)


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

      Click here

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

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) Click here

    OK

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


    1. Disconnect the P57 air conditioning amplifier assembly connector.

    2. Disconnect the P28 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
      P57-14 (TR) - P28-1 Always Below 1 Ω
      P57-1 (SG-1) - P28-2 Always Below 1 Ω
      P57-14 (TR) or P28-1 - Other terminals and body ground Always 10 kΩ or higher
      P57-1 (SG-1) or P28-2 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR