AIR CONDITIONING SYSTEM(except Automatic Air Conditioning System) Cooler Thermistor Circuit

DTC Code DTC Name
Cooler Thermistor Circuit

DESCRIPTION

The 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, which is used to control the air conditioning system. It sends signals to the air conditioning control 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 control 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.

WIRING DIAGRAM

E229251E48

PROCEDURE

  1. CHECK AIR CONDITIONING HARNESS ASSEMBLY (NO. 1 COOLER THERMISTOR - AIR CONDITIONING CONTROL ASSEMBLY)

    1. Disconnect the E26 air conditioning control assembly connector.

    2. Disconnect the P8 No. 1 cooler thermistor connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      P8-1 - E26-6 (TE)

      Always

      Below 1 Ω

      P8-2 - E26-1 (SG-1)

      Always

      Below 1 Ω

      P8-1 - Body ground

      Always

      10 kΩ or higher

      P8-2 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY

    Click here

    OK

  2. INSPECT NO. 1 COOLER THERMISTOR

    1. Remove the No. 1 cooler thermistor.

      Click here

      E293839C01

      *a

      Component without harness connected

      (No. 1 Cooler Thermistor)

      *b

      Sensing Portion

      *c

      Resistance (kΩ)

      *d

      Temperature (°C (°F))

      *e

      Allowable Range

      -

      -

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      1 - 2

      -30°C (-22°F)

      47.59 to 49.99 kΩ

      -25°C (-13°F)

      35.12 to 36.76 kΩ

      -20°C (-4°F)

      26.19 to 27.33 kΩ

      -15°C (5°F)

      19.71 to 20.50 kΩ

      -10°C (14°F)

      14.97 to 15.53 kΩ

      -5°C (23°F)

      11.47 to 11.86 kΩ

      0°C (32°F)

      8.87 to 9.14 kΩ

      5°C (41°F)

      6.88 to 7.12 kΩ

      10°C (50°F)

      5.39 to 5.59 kΩ

      15°C (59°F)

      4.25 to 4.41 kΩ

      20°C (68°F)

      3.37 to 3.51 kΩ

      25°C (77°F)

      2.70 to 2.82 kΩ

      30°C (86°F)

      2.17 to 2.27 kΩ

      35°C (95°F)

      1.76 to 1.84 kΩ

      40°C (104°F)

      1.43 to 1.51 kΩ

      45°C (113°F)

      1.17 to 1.24 kΩ

      50°C (122°F)

      0.97 to 1.02 kΩ

      55°C (131°F)

      0.80 to 0.85 kΩ

      60°C (140°F)

      0.66 to 0.71 kΩ

      65°C (149°F)

      0.56 to 0.59 kΩ

      70°C (158°F)

      0.47 to 0.50 kΩ

      75°C (167°F)

      0.40 to 0.42 kΩ

      80°C (176°F)

      0.34 to 0.36 kΩ

      85°C (185°F)

      0.29 to 0.31 kΩ
      Note:

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

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

      Tip:

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

    Result

    Proceed to

    OK

    NG
    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

    Click hereClick hereClick here

    NG

    REPLACE NO. 1 COOLER THERMISTOR

    Click here