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Home >> Lexus >> 2008 >> IS 250 AWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning >> Air Conditioning System >> DTC B1423/23 Pressure Sensor Circuit >> Inspection Procedure

Inspection Procedure

  1. CHECK REFRIGERANT 
    1. Check the sight glass of the cooler unit refrigerant liquid pipe.
      1. Prepare the vehicle according to the chart below.
        ITEM DESCRIPTION

        Item Condition
        Vehicle Doors Fully open
        Temperature Setting MAX COLD
        Blower Speed HI
        A/C ON
      2. Compare the sight glass to the following chart.
        Fig 1: Identifying Sight Glass
        G05831415Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        ITEM DESCRIPTION

        Item Symptom Amount of Refrigerant Corrective Actions
        1 Bubbles visible Insufficient(1)
        1. Check for gas leakage and repair if necessary
        2. Add refrigerant until bubbles disappear
        2 No bubbles visible Empty, insufficient, or excessive Refer to 3 and 4
        3 No temperature difference between compressor inlet and outlet Empty or nearly empty
        1. Check for gas leakage with gas leak detector and repair if necessary
        2. Evacuate A/C system and recharge with proper amount of refrigerant
        4 Considerable temperature difference between compressor inlet and outlet Proper or excessive Refer to 5 and 6
        5 Immediately after air conditioning is turned OFF, refrigerant clears Excessive
        1. Recover refrigerant
        2. Evacuate A/C system and recharge with proper amount of refrigerant
        6 Immediately after air conditioning is turned OFF, refrigerant foams and then becomes clear Proper -
        (1) Bubbles in the sight glass with the vehicle interior temperature above 35°C (95°F) can be considered normal if cooling is sufficient.

    NG: CHARGE REFRIGERANT 

    OK: Go to Next Step 

  2. CHECK WIRE HARNESS (PRESSURE SENSOR - A/C AMPLIFIER) 
    1. Disconnect the pressure sensor connector.
    2. Disconnect the A/C amplifier connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      B7-2 (PR) - J58-13 (PRE) Always Below 1 Ω
      B7-3 (+) - J58-26 (S5-2) Always Below 1 Ω
      B7-1 (-) - J58-38 (SG-2) Always Below 1 Ω
      J58-13 (PRE) - Body ground Always 10 kΩ or higher
      J58-26 (S5-2) - Body ground Always 10 kΩ or higher
      J58-38 (SG-2) - Body ground Always 10 kΩ or higher
      4. Fig 2: Identifying A/C Amplifier Connector And J58 Connector Terminals
      G05831416Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  3. INSPECT PRESSURE SENSOR 
    1. Install the manifold gauge set (See ON-VEHICLE INSPECTION  ).
    2. Connect the three 1.5 V dry cell batterie's positive (+) lead to terminal 3 and the negative (-) lead to terminal 1. Then connect the voltmeter's positive (+) lead to terminal 2 and the negative (-) lead to terminal 1. Measure the voltage.

      OK: The voltage changes according to refrigerant pressure, as shown in the graph. 

      Result 

      DTC RESULT DESCRIPTION

      Result Proceed to
      NG A
      OK (When troubleshooting according to the DTC) B
      OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE) C
      3. Fig 3: Measuring Voltage And Refrigerant Graph
      G04978935Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    B: REPLACE AIR CONDITIONING AMPLIFIER 

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

    A: REPLACE PRESSURE SENSOR 

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