AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System), Diagnostic DTC:B1413/13

DTC Code DTC Name
B1413/13 Evaporator Temperature Sensor Circuit

DESCRIPTION

The No. 1 cooler thermistor (evaporator temperature sensor) is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air 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 temperature of the cooled air 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
B1413/13 An open or short in the No. 1 cooler thermistor circuit.

  • No. 1 cooler thermistor

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A0059EZE59
*a No. 1 Cooler Thermistor
*b Air Conditioning Harness Assembly
*c Air Conditioning Amplifier Assembly

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (NO. 1 COOLER THERMISTOR)


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

      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 column.
      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 SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

  2. INSPECT NO. 1 COOLER THERMISTOR


    1. Remove the No. 1 cooler thermistor Click here.

      A00545QE03

    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

      Tech Tips

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

      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.


    NG

    REPLACE NO. 1 COOLER THERMISTOR Click here

    OK

  3. CHECK AIR CONDITIONING HARNESS ASSEMBLY


    1. A0058O9E02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to No. 1 Cooler Thermistor)
      *2

      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
      z3-6 (TEA) - 1 Always Below 1 Ω
      z3-5 (SGA) - 2 Always Below 1 Ω
      z3-6 (TEA) - Body ground Always 10 kΩ or higher
      z3-5 (SGA) - Body ground Always 10 kΩ or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here