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

DTC Code DTC Name
B1413 Evaporator Temperature Sensor Circuit

DESCRIPTION

The No. 1 cooler thermistor is installed on the evaporator in the air conditioner unit to detect the cooled air temperature that has passed through the evaporator and control the air conditioning. It sends appropriate signals to the air conditioning amplifier assembly. The resistance of the No. 1 cooler thermistor changes in accordance with the cooled air temperature that has passed through the evaporator. 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 No. 1 cooler thermistor and reads voltage changes as the resistance of the No. 1 cooler thermistor changes. This sensor is used for frost prevention.

DTC Code DTC Detection Condition Trouble Area
B1413 An open or short in the No. 1 cooler thermistor circuit is detected for 8.5 minutes or more.

  • No. 1 cooler thermistor

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A01WYUQE54
*a No. 1 Cooler Thermistor
*b Air Conditioning Harness Assembly
*c Air Conditioning Amplifier Assembly

PROCEDURE


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


    1. Use the Data List to check if the No. 1 cooler thermistor is functioning properly Click here.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Evaporator Fin Thermistor

      No. 1 cooler thermistor /

      Min.: -29.7°C (-21.46°F)

      Max.: 59.55°C (139.19°F)

      		 Actual evaporator temperature displayed

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

      Short in the circuit: 59.55°C (139.19°F).
      OK
      The display is as specified in the normal condition.
      Result
      Result Proceed to
      OK (When troubleshooting according to problem symptoms table) A
      OK (When troubleshooting according to the DTC) B
      NG C

    A

    PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

  2. INSPECT NO. 1 COOLER THERMISTOR

    A01WZYQE04

    1. Remove the 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).

      Text in Illustration
      *a Sensor
      *b Resistance
      *c Allowable Range
      *d Temperature
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE NO. 1 COOLER THERMISTOR Click here

    C

    REPLACE NO. 1 COOLER THERMISTOR Click here

    A

  3. INSPECT AIR CONDITIONING HARNESS ASSEMBLY


    1. A01X4BTE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Cooler Thermistor)
      *b

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

      Remove the air conditioning harness assembly.


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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z54-6 (TEA) - 2 Always Below 1 Ω
      z54-5 (SGA) - 1 Always Below 1 Ω
      z54-6 (TEA) - Body ground Always 10 kΩ or higher
      z54-5 (SGA) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    B

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here

    C

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here