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Home >> Lexus >> 2007 >> GS 450h >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning >> Air Conditioning System >> DTC B1462/62 Room Humidity Sensor Circuit >> Inspection Procedure

Inspection Procedure

  1. READ VALUE OF INTELLIGENT TESTER (HUMIDITY SENS) 
    1. Connect the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the power switch ON (IG) and push the intelligent tester main switch on.
    3. Select the item below in the DATA LIST, and read the display on the intelligent tester.

      A/C amplifier 

      DATA LIST - A/C AMPLIFIER

      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      HUMIDITY SENS (Humidity sensor) Humidity Sensor / Min.: 0%, Max.: 100% Actual room humidity is displayed -

      OK: 

      The display is as specified in the normal condition. 

      Result 

      RESULT REFERENCE

      Result Proceed to
      NG A
      OK (Checking from the PROBLEM SYMPTOMS TABLE) B
      OK (Checking from the DTC) C

    B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

    C: REPLACE AIR CONDITIONING AMPLIFIER 

    A: GO TO Next Step 

  2. CHECK WIRE HARNESS (ROOM TEMPERATURE SENSOR - A/C AMPLIFIER) 
    1. Disconnect the K33 room temperature sensor connector.
    2. Disconnect the K52 A/C amplifier connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      K33-3 (RH) - K52-15 (RH) Below 1 Ω
      K33-4 (S5) - K52-7 (S5-1) Below 1 Ω
      K33-2 (-) - K52-19 (SG-1) Below 1 Ω
      K52-19 (SG-1) - Body ground 10 kΩ or higher
      K52-15 (RH) - Body ground Below 1 Ω
      K52-7 (S5-1) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 1: Identifying Room Temperature Sensor And A/C Amplifier Connectors
    G05306852Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO Next Step 

  3. CHECK AIR CONDITIONING AMPLIFIER (S5-1 - SG-1 VOLTAGE) 
    1. Remove the A/C amplifier with its connectors still connected.
    2. Measure the voltage of the connector.

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Humidity Condition Specified Condition
      K52-7 (S5-1) - K52-19 (SG-1) Power switch ON (IG) 4.5 to 5.5 V
      K52-7 (S5-1) - K52-19 (SG-1) Power switch OFF Below 1 V

    NG: REPLACE AIR CONDITIONING AMPLIFIER 

    Fig 2: Identifying Air Conditioning Amplifier (S5-1 - SG-1 Voltage)
    G05297779Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO Next Step 

  4. INSPECT ROOM TEMPERATURE SENSOR (ROOM HUMIDITY SENSOR) 
    1. Remove the room temperature sensor.
    2. Measure the voltage of the sensor.

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Humidity Condition Specified Condition
      2 (-) - 3 (RH) 10% 0.70 to 1.08 V
      2 (-) - 3 (RH) 20% 0.72 to 1.57 V
      2 (-) - 3 (RH) 30% 1.13 to 1.95 V
      2 (-) - 3 (RH) 40% 1.61 to 2.24 V
      2 (-) - 3 (RH) 50% 1.99 to 2.46 V
      2 (-) - 3 (RH) 60% 2.26 to 2.66 V
      2 (-) - 3 (RH) 70% 2.48 to 2.85 V
      2 (-) - 3 (RH) 80% 2.68 to 3.04 V
      2 (-) - 3 (RH) 90% 2.87 to 3.05 V
      NOTE:
      • Do not touch the humidity sensor as body heat will affect the inspection results. When performing the inspection, hold the sensor by its connector.
      • Allow the sensor to acclimate to the ambient temperature and humidity before performing the inspection.
      • The standard voltages in the table above are based on inspections performed when the ambient temperature is 25°C (77°F).

    NG: REPLACE ROOM TEMPERATURE SENSOR 

    Fig 3: Identifying Room Temperature Sensor Connector With Voltage Graph
    G05306854Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE AIR CONDITIONING AMPLIFIER 

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