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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 91 (Heating / Air Conditioning System (HV) - Diagnostic Codes (2 Of 3)) >> AIR CONDITIONING SYSTEM (for HV Model) >> DTC P0534-7A: Refrigerant Gas Fluid Leak or Seal Failure [11/2023 - ] >> Procedure

DTC P0534-7A: Refrigerant Gas Fluid Leak or Seal Failure [11/2023 - ]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK REFRIGERANT PRESSURE 

    Pre-procedure1

    1. Install a manifold gauge set.

      HINT: 

      Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    2. Prepare the vehicle according to the table below.

      Measurement Condition

      Item Condition
      Doors Fully open
      A/C Switch On
      Recirculation/fresh Control Switch Recirculation
      Set Temperature MAX COLD
      Blower Speed HI
      Air Conditioning Air Inlet Temperature 25 to 35°C (77 to 95°F)

      Procedure1

    3. Compare the values displayed in the Data List and on the manifold gauge.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Air conditioning pressure sensor -32768 to 32767 kPa (gauge) (-32.768 to 32.767 MPaG) Actual refrigerant pressure displayed
      • Refrigerant line (gas leak etc.)
      • Air conditioning pressure sensor circuit malfunction

      Body Electrical > Air Conditioner > Data List 

      Tester Display
      Regulator Pressure Sensor

      Result

      Result Proceed to
      Data List value and manifold gauge set value do not match A
      Data List value matches manifold gauge set value B

      Post-procedure1

    4. None

    Result: 

    B 

    INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET. Refer to  ON-VEHICLE INSPECTION [12/2019 - ] 

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - POWER SOURCE) 

    Pre-procedure1

    1. Disconnect the A24 air conditioning pressure sensor connector.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.
      GTY926230Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Air Conditioning Pressure Sensor)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A24-3 (+) - Body ground Ignition switch ON 4.75 to 5.25 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - BODY GROUND) 

    Pre-procedure1

    1. Disconnect the A24 air conditioning pressure sensor connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A24-1 (-) - Body ground Always Below 1 Ω
      GTY926186Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Air Conditioning Pressure Sensor)

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the A24 air conditioning pressure sensor connector.
    2. Disconnect the H63 air conditioning amplifier assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A24-2 (PR) - H63-6 (PRE) Always Below 1 Ω
      A24-2 (PR) or H63-6 (PRE) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY (SENSOR SIGNAL CIRCUIT) 
    NOTE:
    • If refrigerant pressure on the high pressure side becomes extremely high, the fail-safe function stops compressor operation.
    • It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the malfunction may recur after a while.

    HINT: 

    When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to operation of the ambient temp. sensor (cooler thermistor) and the evaporator temp. sensor (No. 1 cooler thermistor) to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment.

    Pre-procedure1

    1. Connect the H63 air conditioning amplifier assembly connector.
    2. Connect the A24 air conditioning pressure sensor connector.
    3. Prepare the vehicle according to the table below.

      Measurement Condition

      Item Condition
      Doors Fully open
      A/C Switch On
      Recirculation/fresh Control Switch Recirculation
      Set Temperature MAX COLD
      Blower Speed HI
      Air Conditioning Air Inlet Temperature 25 to 35°C (77 to 95°F)

      Procedure1

    4. Measure the voltage according to the value(s) in the table below.
      GTY886400Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Air Conditioning Amplifier Assembly)      		 - -

      Standard Voltage

      Tester Connection Condition Specified Condition
      H63-6 (PRE) - Body ground A/C Switch ON (When compressor with motor assembly running) 0.74 to 4.61 V
    5. Read the Data List according to the display on the GTS.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Air conditioning pressure sensor -32768 to 32767 kPa (gauge) (-32.768 to 32.767 MPaG) Actual refrigerant pressure displayed
      • Refrigerant line (gas leak etc.)
      • Air conditioning pressure sensor circuit malfunction

      Body Electrical > Air Conditioner > Data List 

      Tester Display
      Regulator Pressure Sensor

      OK

      The voltage and value displayed in the Data List change.

      Result

      Result Proceed to
      OK A
      NG (The voltage changes but the value displayed in the Data List does not change.) B
      NG (The voltage does not change.) C

      Post-procedure1

    6. None

    Result: 

    A 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    B 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    C 

    REPLACE AIR CONDITIONING PRESSURE SENSOR. Refer to  REMOVAL [10/2022 - ] 

  6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the A24 air conditioning pressure sensor connector.
    2. Disconnect the H63 air conditioning amplifier assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A24-1 (-) - H63-15 (SG-4) Always Below 1 Ω
      A24-1 (-) or H63-15 (SG-4) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the A24 air conditioning pressure sensor connector.
    2. Disconnect the H63 air conditioning amplifier assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A24-3 (+) - H63-11 (S5-3) Always Below 1 Ω
      A24-3 (+) or H63-11 (S5-3) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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