AIR CONDITIONING SYSTEM, Diagnostic DTC:B1411/11

DTC Code DTC Name
B1411/11 Room Temperature Sensor Circuit

DESCRIPTION

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control the air conditioning AUTO mode. The resistance of the 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 A/C amplifier 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 appropriate signals to the A/C amplifier. The room temperature sensor is integrated with the room humidity sensor.

DTC No. DTC Detection Condition Trouble Area
B1411/11 Open or short in room temperature sensor circuit
  • Room temperature sensor

  • Harness or connector between room temperature sensor and A/C amplifier

  • A/C amplifier

WIRING DIAGRAM

A01JA9GE13

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the intelligent tester on.

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

    5. Check the value(s) by referring to the table below.

      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 cabin temperature displayed -
      OK
      The display is as specified in the Normal Condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B
    C
    A
  2. INSPECT ROOM TEMPERATURE SENSOR


    1. Remove the room temperature sensor.

    2. A01J8UGE19
      Text in Illustration
      *1

      Component without harness connected

      (Room Temperature Sensor)

      *2 Sensing Portion

      Disconnect the room temperature sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L44-1 (+) - L44-2 (-) 10°C (50°F) 3.00 to 3.73 kΩ
      L44-1 (+) - L44-2 (-) 15°C (59°F) 2.45 to 2.88 kΩ
      L44-1 (+) - L44-2 (-) 20°C (68°F) 1.95 to 2.30 kΩ
      L44-1 (+) - L44-2 (-) 25°C (77°F) 1.60 to 1.80 kΩ
      L44-1 (+) - L44-2 (-) 30°C (86°F) 1.28 to 1.47 kΩ
      L44-1 (+) - L44-2 (-) 35°C (95°F) 1.00 to 1.22 kΩ
      L44-1 (+) - L44-2 (-) 40°C (104°F) 0.80 to 1.00 kΩ
      L44-1 (+) - L44-2 (-) 45°C (113°F) 0.65 to 0.85 kΩ
      L44-1 (+) - L44-2 (-) 50°C (122°F) 0.50 to 0.70 kΩ
      L44-1 (+) - L44-2 (-) 55°C (131°F) 0.44 to 0.60 kΩ
      L44-1 (+) - L44-2 (-) 60°C (140°F) 0.36 to 0.50 kΩ

      Note


      • Hold the sensor only by its connector. Touching the sensor may change the resistance value.

      • When measuring, the sensor temperature must be the same as the ambient temperature.

      Tech Tips

      As the temperature increases, the resistance decreases (see the graph).


    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - A/C AMPLIFIER)


    1. A01JAUIE58

      Disconnect the A/C amplifier connector.

    2. A01J9AEE33
      Text in Illustration
      *1

      Front view of wire harness connector

      (to A/C Amplifier)

      *2

      Front view of wire harness connector

      (to Room Temperature Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L17-29 (TR) - L44-1 (+) Always Below 1 Ω
      L17-34 (SG-1) - L44-2 (-) Always Below 1 Ω
      L17-29 (TR) - Body ground Always 10 kΩ or higher
      L17-34 (SG-1) - Body ground Always 10 kΩ or higher

    NG
    OK