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

E156584E60

PROCEDURE

  1. READ VALUE USING INTELLIGENT TESTER

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

      Table 1. 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.

      Table 2. Result

      Result

      Proceed to

      OK (When troubleshooting according to Problem Symptoms Table)

      A

      OK (When troubleshooting according to the DTC)

      B

      NG

      C

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

    (Click here)

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

  2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

    1. Remove the room temperature sensor (Click here).

      E354470E01

    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.

      Tip:

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

    REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

    (Click here)

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

    1. Disconnect the H38 sensor connector.

      E354472E01

    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
      Table 3. 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)

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR