AIR CONDITIONING SYSTEM (for Manual Air Conditioning System), Diagnostic DTC:B1413

DTC Code DTC Name
B1413 Evaporator Temperature Sensor Circuit

DESCRIPTION

The front evaporator temperature sensor (No. 1 cooler thermistor) is installed on the evaporator in the air conditioner unit to detect the temperature of the cooled air that has passed through the evaporator and to control the air conditioner. It sends signals to the air conditioning amplifier, which changes in accordance with the resistance of the front evaporator temperature sensor (No. 1 cooler thermistor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier applies voltage (5 V) to the front evaporator temperature sensor (No. 1 cooler thermistor) and reads voltage changes as the resistance of the front evaporator temperature sensor (No. 1 cooler thermistor) changes. This sensor is used for frost prevention.

DTC No. DTC Detection Condition Trouble Area
B1413 Open or short in evaporator temperature sensor circuit

  • Front evaporator temperature sensor (No. 1 cooler thermistor)

  • Harness and connector between front evaporator temperature sensor (No. 1 cooler thermistor) and air conditioning amplifier

  • Air conditioning amplifier

WIRING DIAGRAM

A011A8OE01

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (EVAPORATOR FIN THERMISTOR)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

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

    5. According to the display on the intelligent tester, read the Data List.

      Air Conditioner
      Tester Display Measurement Item/Display (Range) Normal Condition Diagnostic Note
      Evaporator Fin Thermistor Evaporator fin thermistor / Min.: -29.7°C (-21.46°F), Max.: 59.55°C (139.19°F) Actual evaporator temperature is displayed

      Open in circuit: -29.7°C (-21.46°F)

      Short in circuit: 59.55°C (139.019°F)
      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 output) C

    B

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

    C

    REPLACE AIR CONDITIONING AMPLIFIER Click here

    A

  2. INSPECT FRONT EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR)


    1. A0119QOE01

      Remove the front evaporator temperature sensor (No. 1 cooler thermistor).

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 - 2 -10°C (14°F) 7.30 to 9.10 kΩ
      -5°C (23°F) 5.65 to 6.95 kΩ
      0°C (32°F) 4.40 to 5.35 kΩ
      5°C (41°F) 3.40 to 4.15 kΩ
      10°C (50°F) 2.70 to 3.25 kΩ
      15°C (59°F) 2.14 to 2.58 kΩ
      20°C (68°F) 1.71 to 2.05 kΩ
      25°C (77°F) 1.38 to 1.64 kΩ
      30°C (86°F) 1.11 to 1.32 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 (see the graph).

    3. Reinstall the front evaporator temperature sensor (No. 1 cooler thermistor).


    NG

    REPLACE FRONT EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - NO. 1 COOLER THERMISTOR)


    1. A0117L3E01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Front Evaporator Temperature Sensor (No. 1 Cooler Thermistor))
      *2

      Front view of wire harness connector

      (to Air Conditioning Amplifier)

      Disconnect the D10 front evaporator temperature sensor (No. 1 cooler thermistor) connector.

    2. Disconnect the D16 air conditioning amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D16-22 (TE) - D10-2 Always Below 1 Ω
      D16-10 (SG-2) - D10-1 Always Below 1 Ω
      D16-22 (TE) - Body ground Always 10 kΩ or higher
      D16-10 (SG-2) - Body ground Always 10 kΩ or higher

    4. Reconnect the air conditioning amplifier connector.

    5. Reconnect the front evaporator temperature sensor (No. 1 cooler thermistor) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER Click here