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AIR CONDITIONING SYSTEM, Diagnostic DTC:B1462/62

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DTC Code DTC Name
B1462/62 Room Humidity Sensor Circuit
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DESCRIPTION

The air conditioning thermistor assembly (humidity sensor) detects cabin humidity. The voltage of the air conditioning thermistor assembly (humidity sensor) changes in accordance with cabin humidity. The air conditioning amplifier assembly reads changes in the air conditioning thermistor assembly (humidity sensor).

The humidity sensor is integrated with the air conditioning thermistor assembly.

DTC No. DTC Detecting Condition Trouble Area
B1462/62 Open or short in humidity sensor circuit
  • Air conditioning thermistor assembly (humidity sensor)

  • Harness or connector between air conditioning thermistor assembly (humidity sensor) and air conditioning amplifier assembly

  • Air conditioning amplifier assembly

Tip:

The whole air conditioning thermistor assembly should be replaced if the humidity sensor is malfunctioning.

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WIRING DIAGRAM

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PROCEDURE


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    READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    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.

      Table 1. Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Humidity Sensor

      Humidity sensor /

      Min.: 0.00%, Max.: 100.00%

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

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    CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Disconnect the T3 air conditioning thermistor assembly (humidity sensor) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      T3-5 (S5V) - Body ground Power switch off Below 1 V
      T3-5 (S5V) - Body ground Power switch on (IG) 4.5 to 5.5 V

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    INSPECT AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR)


    1. A0006ODE02
      A0008Z8E03

      Reconnect the T3 air conditioning thermistor assembly (humidity sensor) connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (SEG3) - 3 (RH) Humidity is 5 to 15 % 1.01 V
      1 (SEG3) - 3 (RH) Humidity is 15 to 25 % 1.37 V
      1 (SEG3) - 3 (RH) Humidity is 25 to 35 % 1.73 V
      1 (SEG3) - 3 (RH) Humidity is 35 to 45 % 2.09 V
      1 (SEG3) - 3 (RH) Humidity is 45 to 55 % 2.45 V
      1 (SEG3) - 3 (RH) Humidity is 55 to 65 % 2.81 V
      1 (SEG3) - 3 (RH) Humidity is 65 to 75 % 3.17 V
      1 (SEG3) - 3 (RH) Humidity is 75 to 85 % 3.53 V
      1 (SEG3) - 3 (RH) Humidity is 85 to 95 % 3.89 V
      Note:
      • Do not touch the humidity sensor because it may be affected by body temperature and may not work properly.

      • Hold the sensor only by its connector.

      • The output voltage at an ambient temperature of 25°C (77°F) is shown above.

      Tip:

      As the humidity increases, the voltage increases (see the graph).

      Table 2. Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Thermistor Assembly (Humidity Sensor))

      *b Heat Conduction Sheet Part
      *c Voltage (V)
      *d Relative Humidity (%)

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    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the H54 air conditioning amplifier assembly connector.

    2. Disconnect the T3 air conditioning thermistor assembly (humidity sensor) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      T3-3 (RH) - H54-28 (RH) Always Below 1 Ω
      T3-1 (SEG3) - H54-35 (SG-4) Always Below 1 Ω
      T3-3 (RH) - Body ground Always 10 kΩ or higher
      T3-1 (SEG3) - Body ground Always 10 kΩ or higher

    • OK

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

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    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR))


    1. Disconnect the H54 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      T3-5 (S5V) - H54-31 (S5-4) Always Below 1 Ω
      T3-5 (S5V) - Body ground Always 10 kΩ or higher

    • OK

      REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR