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Home >> Lexus >> 2007 >> LX 470 >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning >> Air Conditioning System >> DTC 11 Room Temperature Sensor Circuit >> Inspection Procedure

Inspection Procedure

  1. CHECK VOLTAGE BETWEEN TERMINALS FRTR AND FRSG OF AIR CONDITIONING AMPLIFIER 
    1. Remove the A/C amplifier with the connectors still connected.
    2. Turn the ignition switch ON.
    3. Measure the voltage between terminals FRTR (A48-17) and FRSG (A48-18) of A/C amplifier connector at each temperature.

      Standard voltage: 

      1.8 to 2.2 V at 25°C (77°F) 

      1.2 to 1.6 V at 40°C (104°F) 

      HINT:

      • As the temperature increases, the voltage decreases.
      • However, if DTC 11 is displayed, check and replace the A/C amplifier.
        Fig 1: Checking Voltage Between Terminals FRTR And FRSG Of Air Conditioning Amplifier
        G05284117Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE AIR CONDITIONING AMPLIFIER 

    NG: Go to next step 

  2. INSPECT FRONT ROOM TEMPERATURE SENSOR 
    1. Disconnect the R7 front room temperature sensor connector.
    2. Measure the resistance between terminals 1 and 2 the of front room temperature sensor connector at each temperature.

      Standard resistance: 

      1.65 to 1.75 kΩ at 25°C (77°F) 

      0.55 to 0.65 kΩ at 50°C (122°F) 

      HINT:

      As the temperature increases, the resistance decreases.

    NG: REPLACE FRONT ROOM TEMPERATURE SENSOR 

    Fig 2: Identifying Front Room Temperature Sensor Connector Terminals
    G05284118Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  3. CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - FRONT ROOM TEMPERATURE SENSOR) 

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: REPLACE AIR CONDITIONING AMPLIFIER