AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System), Diagnostic DTC:B1430/21, B1431/-21

DTC Code DTC Name
B1430/21 Open in Room Temperature Sensor Circuit
B1431/-21 Short in Room Temperature Sensor Circuit

DESCRIPTION

The cooler (room temp. sensor) thermistor is installed in the instrument panel to detect the cabin temperature which is used to control the heater and air conditioning system AUTO mode. The resistance of the cooler (room temp. sensor) thermistor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning control assembly applies a voltage (5 V) to the cooler (room temp. sensor) thermistor and reads voltage changes due to changes in the resistance of the cooler (room temp. sensor) thermistor.

DTC No. DTC Detection Condition Trouble Area
B1430/21 Open in room temperature sensor circuit
  • Cooler (room temp. sensor) thermistor

  • Harness or connector between cooler (room temp. sensor) thermistor and air conditioning control assembly

  • Air conditioning control assembly

B1431/-21 Short in room temperature sensor circuit
  • Cooler (room temp. sensor) thermistor

  • Harness or connector between cooler (room temp. sensor) thermistor and air conditioning control assembly

  • Air conditioning control assembly

WIRING DIAGRAM

A004JY2E02
*a COOLER (ROOM TEMP. SENSOR) THERMISTOR
*b AIR CONDITIONING CONTROL ASSEMBLY

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

    5. Check the value(s) by referring to the table below.

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

      Room Temperature Sensor

      (Room Temp)

      Room Temperature Sensor /

      min.: -72.47°C (-98.4°F)

      max.: 193.82°C (380.9°F)

      Actual cabin temperature displayed -
      OK
      The display is as specified in the normal condition column.
      Result
      Result Proceed to
      OK (When troubleshooting according to the DTC) A
      OK (When troubleshooting according to Problem Symptoms Table) B
      NG C

    B
    C
    A
  2. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check the DTCs Click here.

      OK
      DTC is not output.

    OK
    NG
  3. INSPECT COOLER (ROOM TEMP. SENSOR) THERMISTOR


    1. Remove the cooler (room temp. sensor) thermistor Click here.

    2. Inspect the cooler (room temp. sensor) thermistor Click here.


    NG
    OK
  4. CHECK HARNESS AND CONNECTOR (COOLER (ROOM TEMP. SENSOR) THERMISTOR - AIR CONDITIONING CONTROL ASSEMBLY)


    1. Disconnect the D20 air conditioning control assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D67-1 - D20-5(TR) Always Below 1 Ω
      D67-2 - D20-6(SG) Always Below 1 Ω
      D67-1 - Body ground Always 10 kΩ or higher
      D67-2 - Body ground Always 10 kΩ or higher

    OK
    NG