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

E140288E58

PROCEDURE

  1. READ VALUE USING INTELLIGENT TESTER

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

      Table 1. 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.

      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 NO. 1 COOLER THERMISTOR

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

      E354477E01

    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.

      Tip:

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

    REPLACE NO. 1 COOLER THERMISTOR

    (Click here)

  3. CHECK AIR CONDITIONING HARNESS ASSEMBLY

    1. E354479E01

      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

      z19-6 (TEA) - 1

      Always

      Below 1 Ω

      z19-5 (SGA) - 2

      Always

      Below 1 Ω

      z19-6 (TEA) - Body ground

      Always

      10 kΩ or higher

      z19-5 (SGA) - Body ground

      Always

      10 kΩ or higher
      Table 3. 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)

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

    (Click here)

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY

    (Click here)